Update Your User Class

namespace RankMath;

use WP_User;

defined( 'ABSPATH' ) || exit;

/**
* User class.
*/
class User extends Metadata {

/**
* The type of object the metadata is for.
*
* @var string
*/
protected $meta_type = 'user';

/**
* Get User instance.
*
* @param WP_User|object|int $user User ID or user object.
* @return User|false User object or false if not found.
*/
public static function get( $user = 0 ) {
if ( is_int( $user ) && 0 === absint( $user ) ) {
$user = $GLOBALS['wp_query']->get_queried_object();
}
if ( is_object( $user ) && isset( $user->ID ) ) {
$user = $user->ID;
}

if ( empty( $user ) || ( ! is_scalar( $user ) && ! is_object( $user ) ) ) {
return null;
}

// Ensure $user is a scalar value (int or string)
if ( is_scalar( $user ) ) {
if ( isset( self::$objects[ $user ] ) && 'user' === self::$objects[ $user ]->meta_type ) {
return self::$objects[ $user ];
}

$_user = new self( get_user_by( 'id', $user ) );
$_user->object_id = $user;
self::$objects[ $user ] = $_user;

return $_user;
}

// If $user is an array or an object, return null
return null;
}

/**
* Get user meta data.
*
* @param string $key Meta key.
* @param mixed $user User ID or user object.
* @param string $default Default value to use when metadata does not exists.
* @return mixed
*/
public static function get_meta( $key, $user = 0, $default = '' ) {
$user = self::get( $user );

if ( is_null( $user ) || ! $user instanceof self || ! $user->is_found() ) {
return $default;
}

return $user->get_metadata( $key, $default );
}

}