diff --git a/lib/private/AllConfig.php b/lib/private/AllConfig.php
index 403f8b4f68dfd..dfaa1d476bf4f 100644
--- a/lib/private/AllConfig.php
+++ b/lib/private/AllConfig.php
@@ -227,6 +227,7 @@ public function deleteAppValues($appName) {
 	 * @param string $preCondition only update if the config value was previously the value passed as $preCondition
 	 * @throws \OCP\PreConditionNotMetException if a precondition is specified and is not met
 	 * @throws \UnexpectedValueException when trying to store an unexpected value
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function setUserValue($userId, $appName, $key, $value, $preCondition = null) {
 		if (!is_int($value) && !is_float($value) && !is_string($value)) {
@@ -253,7 +254,8 @@ public function setUserValue($userId, $appName, $key, $value, $preCondition = nu
 	 * @param string $appName the appName that we stored the value under
 	 * @param string $key the key under which the value is being stored
 	 * @param mixed $default the default value to be returned if the value isn't set
-	 * @return string|null
+	 * @return string
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function getUserValue($userId, $appName, $key, $default = '') {
 		if ($userId === null || $userId === '') {
@@ -268,6 +270,7 @@ public function getUserValue($userId, $appName, $key, $default = '') {
 	 * @param string $userId the userId of the user that we want to store the value under
 	 * @param string $appName the appName that we stored the value under
 	 * @return string[]
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function getUserKeys($userId, $appName) {
 		return \OC::$server->get(UserPreferences::class)->getKeys($userId, $appName);
@@ -279,6 +282,7 @@ public function getUserKeys($userId, $appName) {
 	 * @param string $userId the userId of the user that we want to store the value under
 	 * @param string $appName the appName that we stored the value under
 	 * @param string $key the key under which the value is being stored
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function deleteUserValue($userId, $appName, $key) {
 		\OC::$server->get(UserPreferences::class)->deletePreference($userId, $appName, $key);
@@ -288,15 +292,20 @@ public function deleteUserValue($userId, $appName, $key) {
 	 * Delete all user values
 	 *
 	 * @param string $userId the userId of the user that we want to remove all values from
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function deleteAllUserValues($userId) {
-		\OC::$server->get(UserPreferences::class)->dropUserPreferences($userId);
+		if ($userId === null) {
+			return;
+		}
+		\OC::$server->get(UserPreferences::class)->deleteAllPreferences($userId);
 	}
 
 	/**
 	 * Delete all user related values of one app
 	 *
 	 * @param string $appName the appName of the app that we want to remove all values from
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function deleteAppFromAllUsers($appName) {
 		\OC::$server->get(UserPreferences::class)->deleteApp($appName);
@@ -311,6 +320,7 @@ public function deleteAppFromAllUsers($appName) {
 	 *                 [ $appId =>
 	 *                 [ $key => $value ]
 	 *                 ]
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function getAllUserValues(?string $userId): array {
 		if ($userId === null || $userId === '') {
@@ -334,6 +344,7 @@ public function getAllUserValues(?string $userId): array {
 	 * @param string $key the key to get the value for
 	 * @param array $userIds the user IDs to fetch the values for
 	 * @return array Mapped values: userId => value
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function getUserValueForUsers($appName, $key, $userIds) {
 		return \OC::$server->get(UserPreferences::class)->searchValuesByUsers($appName, $key, ValueType::MIXED, $userIds);
@@ -346,6 +357,7 @@ public function getUserValueForUsers($appName, $key, $userIds) {
 	 * @param string $key the key to get the user for
 	 * @param string $value the value to get the user for
 	 * @return array of user IDs
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function getUsersForUserValue($appName, $key, $value) {
 		return \OC::$server->get(UserPreferences::class)->searchUsersByValueString($appName, $key, $value);
@@ -358,6 +370,7 @@ public function getUsersForUserValue($appName, $key, $value) {
 	 * @param string $key the key to get the user for
 	 * @param string $value the value to get the user for
 	 * @return array of user IDs
+	 * @deprecated 31.0.0 - use {@see IUserPreferences} directly
 	 */
 	public function getUsersForUserValueCaseInsensitive($appName, $key, $value) {
 		if ($appName === 'settings' && $key === 'email') {
diff --git a/lib/private/UserPreferences.php b/lib/private/UserPreferences.php
index 943a1143fd407..868e42c5c1ecc 100644
--- a/lib/private/UserPreferences.php
+++ b/lib/private/UserPreferences.php
@@ -386,7 +386,9 @@ public function searchUsersByValueString(string $app, string $key, string|array
 		$qb->select('userid');
 		$qb->where($qb->expr()->eq('appid', $qb->createNamedParameter($app)));
 		$qb->andWhere($qb->expr()->eq('configkey', $qb->createNamedParameter($key)));
-		if (is_string($value)) {
+		if (is_array($value)) {
+			$qb->andWhere($qb->expr()->in('configvalue', $qb->createNamedParameter($value, IQueryBuilder::PARAM_STR_ARRAY)));
+		} else {
 			if ($caseInsensitive) {
 				$configValueColumn = ($this->connection->getDatabaseProvider() === IDBConnection::PLATFORM_ORACLE) ? $qb->expr()->castColumn('configvalue', IQueryBuilder::PARAM_STR) : 'configvalue';
 				$qb->andWhere($qb->expr()->eq(
@@ -396,8 +398,6 @@ public function searchUsersByValueString(string $app, string $key, string|array
 			} else {
 				$qb->andWhere($qb->expr()->eq('configvalue', $qb->createNamedParameter($value)));
 			}
-		} else {
-			$qb->andWhere($qb->expr()->in('configvalue', $qb->createNamedParameter($value, IQueryBuilder::PARAM_STR_ARRAY)));
 		}
 
 		$userIds = [];
@@ -452,7 +452,7 @@ public function getValueMixed(
 		string $userId,
 		string $app,
 		string $key,
-		?string $default = '',
+		string $default = '',
 		?bool $lazy = false
 	): ?string {
 		try {
@@ -461,11 +461,6 @@ public function getValueMixed(
 			return $default;
 		}
 
-		// in case $default is null we will convert is to string unless key is not known
-		if ($default === null && !$this->hasKey($userId, $app, $key, $lazy)) {
-			return null;
-		}
-
 		return $this->getTypedValue(
 			$userId,
 			$app,
@@ -1337,7 +1332,7 @@ public function deleteApp(string $app): void {
 		$this->clearCacheAll();
 	}
 
-	public function dropUserPreferences(string $userId): void {
+	public function deleteAllPreferences(string $userId): void {
 		$this->assertParams($userId, '', allowEmptyApp: true);
 		$qb = $this->connection->getQueryBuilder();
 		$qb->delete('preferences')
diff --git a/lib/public/UserPreferences/IUserPreferences.php b/lib/public/UserPreferences/IUserPreferences.php
index e48facdd5ab70..edf99230ccb88 100644
--- a/lib/public/UserPreferences/IUserPreferences.php
+++ b/lib/public/UserPreferences/IUserPreferences.php
@@ -519,7 +519,7 @@ public function deleteApp(string $app): void;
 	 * @param string $userId id of the user
 	 * @since 31.0.0
 	 */
-	public function dropUserPreferences(string $userId): void;
+	public function deleteAllPreferences(string $userId): void;
 
 	/**
 	 * Clear the cache for a single user