diff --git a/apps/dav/lib/CalDAV/CalendarImpl.php b/apps/dav/lib/CalDAV/CalendarImpl.php
index 5f912da732e..be88beff370 100644
--- a/apps/dav/lib/CalDAV/CalendarImpl.php
+++ b/apps/dav/lib/CalDAV/CalendarImpl.php
@@ -11,6 +11,7 @@ namespace OCA\DAV\CalDAV;
 use Generator;
 use OCA\DAV\CalDAV\Auth\CustomPrincipalPlugin;
 use OCA\DAV\CalDAV\InvitationResponse\InvitationResponseServer;
+use OCA\DAV\Connector\Sabre\Server;
 use OCP\Calendar\CalendarExportOptions;
 use OCP\Calendar\Exceptions\CalendarException;
 use OCP\Calendar\ICalendarExport;
@@ -161,7 +162,7 @@ class CalendarImpl implements ICreateFromString, IHandleImipMessage, ICalendarIs
 	private function createFromStringInServer(
 		string $name,
 		string $calendarData,
-		\OCA\DAV\Connector\Sabre\Server $server,
+		Server $server,
 	): void {
 		/** @var CustomPrincipalPlugin $plugin */
 		$plugin = $server->getPlugin('auth');
diff --git a/apps/dav/lib/CalDAV/EmbeddedCalDavServer.php b/apps/dav/lib/CalDAV/EmbeddedCalDavServer.php
index d9d6d840c5e..6037fa3194e 100644
--- a/apps/dav/lib/CalDAV/EmbeddedCalDavServer.php
+++ b/apps/dav/lib/CalDAV/EmbeddedCalDavServer.php
@@ -13,6 +13,7 @@ use OCA\DAV\AppInfo\PluginManager;
 use OCA\DAV\CalDAV\Auth\CustomPrincipalPlugin;
 use OCA\DAV\CalDAV\Auth\PublicPrincipalPlugin;
 use OCA\DAV\CalDAV\Publishing\PublishPlugin;
+use OCA\DAV\CalDAV\Schedule\IMipPlugin;
 use OCA\DAV\Connector\Sabre\AnonymousOptionsPlugin;
 use OCA\DAV\Connector\Sabre\BlockLegacyClientPlugin;
 use OCA\DAV\Connector\Sabre\CachingTree;
@@ -94,7 +95,7 @@ class EmbeddedCalDavServer {
 			Server::get(IURLGenerator::class)
 		));
 		if ($appConfig->getValueString('dav', 'sendInvitations', 'yes') === 'yes') {
-			$this->server->addPlugin(Server::get(\OCA\DAV\CalDAV\Schedule\IMipPlugin::class));
+			$this->server->addPlugin(Server::get(IMipPlugin::class));
 		}
 
 		// collection preload plugin
diff --git a/apps/files/tests/Controller/ViewControllerTest.php b/apps/files/tests/Controller/ViewControllerTest.php
index 01aa955a13e..e1a62a9336c 100644
--- a/apps/files/tests/Controller/ViewControllerTest.php
+++ b/apps/files/tests/Controller/ViewControllerTest.php
@@ -301,7 +301,7 @@ class ViewControllerTest extends TestCase {
 		$invokedCountProvideInitialState = $this->exactly(9);
 		$this->initialState->expects($invokedCountProvideInitialState)
 			->method('provideInitialState')
-			->willReturnCallback(function ($key, $data) use ($invokedCountProvideInitialState) {
+			->willReturnCallback(function ($key, $data) use ($invokedCountProvideInitialState): void {
 				if ($invokedCountProvideInitialState->numberOfInvocations() === 9) {
 					$this->assertEquals('isTwoFactorEnabled', $key);
 					$this->assertTrue($data);
diff --git a/apps/files_sharing/tests/Controller/ShareAPIControllerTest.php b/apps/files_sharing/tests/Controller/ShareAPIControllerTest.php
index e6be0342c26..b7ee24fedd8 100644
--- a/apps/files_sharing/tests/Controller/ShareAPIControllerTest.php
+++ b/apps/files_sharing/tests/Controller/ShareAPIControllerTest.php
@@ -16,6 +16,7 @@ use OCP\AppFramework\OCS\OCSException;
 use OCP\AppFramework\OCS\OCSForbiddenException;
 use OCP\AppFramework\OCS\OCSNotFoundException;
 use OCP\Constants;
+use OCP\Files\Cache\ICache;
 use OCP\Files\File;
 use OCP\Files\Folder;
 use OCP\Files\IRootFolder;
@@ -5244,7 +5245,7 @@ class ShareAPIControllerTest extends TestCase {
 		], $result);
 	}
 
-	public function trustedServerProvider(): array {
+	public static function trustedServerProvider(): array {
 		return [
 			'Trusted server' => [true, true],
 			'Untrusted server' => [false, false],
@@ -5272,21 +5273,21 @@ class ShareAPIControllerTest extends TestCase {
 			$nodeId
 		);
 
-		$node = $this->createMock(\OCP\Files\File::class);
+		$node = $this->createMock(File::class);
 		$node->method('getId')->willReturn($nodeId);
 		$node->method('getPath')->willReturn($nodePath);
 		$node->method('getInternalPath')->willReturn(ltrim($nodePath, '/'));
-		$mountPoint = $this->createMock(\OCP\Files\Mount\IMountPoint::class);
+		$mountPoint = $this->createMock(IMountPoint::class);
 		$mountPoint->method('getMountType')->willReturn('local');
 		$node->method('getMountPoint')->willReturn($mountPoint);
 		$node->method('getMimetype')->willReturn('text/plain');
-		$storage = $this->createMock(\OCP\Files\Storage\IStorage::class);
-		$storageCache = $this->createMock(\OCP\Files\Cache\ICache::class);
+		$storage = $this->createMock(IStorage::class);
+		$storageCache = $this->createMock(ICache::class);
 		$storageCache->method('getNumericStorageId')->willReturn(1);
 		$storage->method('getCache')->willReturn($storageCache);
 		$storage->method('getId')->willReturn('home::shareOwner');
 		$node->method('getStorage')->willReturn($storage);
-		$parent = $this->createMock(\OCP\Files\Folder::class);
+		$parent = $this->createMock(Folder::class);
 		$parent->method('getId')->willReturn(2);
 		$node->method('getParent')->willReturn($parent);
 		$node->method('getSize')->willReturn(1234);
@@ -5334,21 +5335,21 @@ class ShareAPIControllerTest extends TestCase {
 			$nodeId
 		);
 
-		$node = $this->createMock(\OCP\Files\File::class);
+		$node = $this->createMock(File::class);
 		$node->method('getId')->willReturn($nodeId);
 		$node->method('getPath')->willReturn($nodePath);
 		$node->method('getInternalPath')->willReturn(ltrim($nodePath, '/'));
-		$mountPoint = $this->createMock(\OCP\Files\Mount\IMountPoint::class);
+		$mountPoint = $this->createMock(IMountPoint::class);
 		$mountPoint->method('getMountType')->willReturn('local');
 		$node->method('getMountPoint')->willReturn($mountPoint);
 		$node->method('getMimetype')->willReturn('text/plain');
-		$storage = $this->createMock(\OCP\Files\Storage\IStorage::class);
-		$storageCache = $this->createMock(\OCP\Files\Cache\ICache::class);
+		$storage = $this->createMock(IStorage::class);
+		$storageCache = $this->createMock(ICache::class);
 		$storageCache->method('getNumericStorageId')->willReturn(1);
 		$storage->method('getCache')->willReturn($storageCache);
 		$storage->method('getId')->willReturn('home::shareOwner');
 		$node->method('getStorage')->willReturn($storage);
-		$parent = $this->createMock(\OCP\Files\Folder::class);
+		$parent = $this->createMock(Folder::class);
 		$parent->method('getId')->willReturn(2);
 		$node->method('getParent')->willReturn($parent);
 		$node->method('getSize')->willReturn(1234);
diff --git a/apps/files_trashbin/tests/Command/ExpireTrashTest.php b/apps/files_trashbin/tests/Command/ExpireTrashTest.php
index 23bf0d8f121..0d0ee98ca7a 100644
--- a/apps/files_trashbin/tests/Command/ExpireTrashTest.php
+++ b/apps/files_trashbin/tests/Command/ExpireTrashTest.php
@@ -110,7 +110,7 @@ class ExpireTrashTest extends TestCase {
 		$this->assertEquals($shouldExpire ? 0 : 1, count($trashFiles));
 	}
 
-	public function retentionObligationProvider(): array {
+	public static function retentionObligationProvider(): array {
 		$hour = 3600; // 60 * 60
 
 		$oneDay = 24 * $hour;
diff --git a/core/AppInfo/Capabilities.php b/core/AppInfo/Capabilities.php
index 67bbfd62b2d..ef599e2b9dc 100644
--- a/core/AppInfo/Capabilities.php
+++ b/core/AppInfo/Capabilities.php
@@ -13,6 +13,7 @@ use OCP\Config\IUserConfig;
 use OCP\IDateTimeZone;
 use OCP\IGroupManager;
 use OCP\IUserSession;
+use OCP\Server;
 
 class Capabilities implements ICapability {
 
@@ -33,7 +34,7 @@ class Capabilities implements ICapability {
 
 		$user = $this->session->getUser();
 		if ($user !== null) {
-			$timezone = \OCP\Server::get(IDateTimeZone::class)->getTimeZone();
+			$timezone = Server::get(IDateTimeZone::class)->getTimeZone();
 
 			$capabilities['user'] = [
 				'language' => $this->userConfig->getValueString($user->getUID(), Application::APP_ID, ConfigLexicon::USER_LANGUAGE),
diff --git a/core/Command/TaskProcessing/Cleanup.php b/core/Command/TaskProcessing/Cleanup.php
index 2ed2cbdec94..7a1b1bea5a7 100644
--- a/core/Command/TaskProcessing/Cleanup.php
+++ b/core/Command/TaskProcessing/Cleanup.php
@@ -12,13 +12,15 @@ use OC\Core\Command\Base;
 use OC\TaskProcessing\Db\TaskMapper;
 use OC\TaskProcessing\Manager;
 use OCP\Files\AppData\IAppDataFactory;
+use OCP\Files\IAppData;
+use OCP\Files\NotFoundException;
 use Psr\Log\LoggerInterface;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 
 class Cleanup extends Base {
-	private \OCP\Files\IAppData $appData;
+	private IAppData $appData;
 
 	public function __construct(
 		protected Manager $taskProcessingManager,
@@ -76,7 +78,7 @@ class Cleanup extends Base {
 			foreach ($textToImageDeletedFileNames as $entry) {
 				$output->writeln("<info>\t - " . 'Deleted appData/core/text2image/' . $entry . '</info>');
 			}
-		} catch (\OCP\Files\NotFoundException $e) {
+		} catch (NotFoundException $e) {
 			// noop
 		}
 		try {
@@ -84,7 +86,7 @@ class Cleanup extends Base {
 			foreach ($audioToTextDeletedFileNames as $entry) {
 				$output->writeln("<info>\t - " . 'Deleted appData/core/audio2text/' . $entry . '</info>');
 			}
-		} catch (\OCP\Files\NotFoundException $e) {
+		} catch (NotFoundException $e) {
 			// noop
 		}
 
diff --git a/tests/lib/Avatar/GuestAvatarTest.php b/tests/lib/Avatar/GuestAvatarTest.php
index b49fcea6ed2..ba14d571e27 100644
--- a/tests/lib/Avatar/GuestAvatarTest.php
+++ b/tests/lib/Avatar/GuestAvatarTest.php
@@ -11,6 +11,7 @@ namespace Test\Avatar;
 
 use OC\Avatar\GuestAvatar;
 use OCP\Files\SimpleFS\InMemoryFile;
+use OCP\IConfig;
 use PHPUnit\Framework\MockObject\MockObject;
 use Psr\Log\LoggerInterface;
 use Test\TestCase;
@@ -35,7 +36,7 @@ class GuestAvatarTest extends TestCase {
 	public function setupGuestAvatar() {
 		/* @var MockObject|LoggerInterface $logger */
 		$logger = $this->createMock(LoggerInterface::class);
-		$config = $this->createMock(\OCP\IConfig::class);
+		$config = $this->createMock(IConfig::class);
 		$this->guestAvatar = new GuestAvatar('einstein', $config, $logger);
 	}
 
diff --git a/tests/lib/Files/Cache/FileAccessTest.php b/tests/lib/Files/Cache/FileAccessTest.php
index 59fa2494ea8..63577ea874c 100644
--- a/tests/lib/Files/Cache/FileAccessTest.php
+++ b/tests/lib/Files/Cache/FileAccessTest.php
@@ -9,8 +9,13 @@ namespace Test\Files\Cache;
 
 use OC\Files\Cache\CacheEntry;
 use OC\Files\Cache\FileAccess;
+use OC\Files\Mount\LocalHomeMountProvider;
+use OC\FilesMetadata\FilesMetadataManager;
+use OC\SystemConfig;
 use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\Files\IMimeTypeLoader;
 use OCP\IDBConnection;
+use OCP\Server;
 use Psr\Log\LoggerInterface;
 use Test\TestCase;
 
@@ -25,15 +30,15 @@ class FileAccessTest extends TestCase {
 		parent::setUp();
 
 		// Setup the actual database connection (assume the database is configured properly in PHPUnit setup)
-		$this->dbConnection = \OCP\Server::get(IDBConnection::class);
+		$this->dbConnection = Server::get(IDBConnection::class);
 
 		// Ensure FileAccess is instantiated with the real connection
 		$this->fileAccess = new FileAccess(
 			$this->dbConnection,
-			\OCP\Server::get(\OC\SystemConfig::class),
-			\OCP\Server::get(LoggerInterface::class),
-			\OCP\Server::get(\OC\FilesMetadata\FilesMetadataManager::class),
-			\OCP\Server::get(\OCP\Files\IMimeTypeLoader::class)
+			Server::get(SystemConfig::class),
+			Server::get(LoggerInterface::class),
+			Server::get(FilesMetadataManager::class),
+			Server::get(IMimeTypeLoader::class)
 		);
 
 		// Clear and prepare `filecache` table for tests
@@ -142,7 +147,7 @@ class FileAccessTest extends TestCase {
 			->values([
 				'storage_id' => $queryBuilder->createNamedParameter(4, IQueryBuilder::PARAM_INT),
 				'root_id' => $queryBuilder->createNamedParameter(40, IQueryBuilder::PARAM_INT),
-				'mount_provider_class' => $queryBuilder->createNamedParameter(\OC\Files\Mount\LocalHomeMountProvider::class),
+				'mount_provider_class' => $queryBuilder->createNamedParameter(LocalHomeMountProvider::class),
 				'mount_point' => $queryBuilder->createNamedParameter('/home/user'),
 				'user_id' => $queryBuilder->createNamedParameter('test'),
 			])
diff --git a/tests/lib/Files/ObjectStore/PrimaryObjectStoreConfigTest.php b/tests/lib/Files/ObjectStore/PrimaryObjectStoreConfigTest.php
index b60b7ca4f83..6015040f199 100644
--- a/tests/lib/Files/ObjectStore/PrimaryObjectStoreConfigTest.php
+++ b/tests/lib/Files/ObjectStore/PrimaryObjectStoreConfigTest.php
@@ -46,7 +46,7 @@ class PrimaryObjectStoreConfigTest extends TestCase {
 				}
 			});
 		$this->config->method('setUserValue')
-			->willReturnCallback(function ($userId, $appName, $key, $value) {
+			->willReturnCallback(function ($userId, $appName, $key, $value): void {
 				$this->userConfig[$userId][$appName][$key] = $value;
 			});