Salesforce App specific showing tabs to profile users

// Apex to change tab visibility for a specific profile
public class UpdateTabVisibility {
    public static void updateTabVisibility(String profileName, String tabName, String visibility) {
        // visibility can be 'DefaultOn', 'DefaultOff', or 'Hidden'
        Profile prof = [SELECT Id, Name FROM Profile WHERE Name = :profileName LIMIT 1];
        MetadataService.MetadataPort service = new MetadataService.MetadataPort();
        service.SessionHeader = new MetadataService.SessionHeader_element();
        service.SessionHeader.sessionId = UserInfo.getSessionId();
        
        MetadataService.Profile profileMD = 
            (MetadataService.Profile) service.readMetadata('Profile', new String[] { prof.Name }).getRecords()[0];
        
        // Update tab setting
        MetadataService.ProfileTabVisibility tabSetting = new MetadataService.ProfileTabVisibility();
        tabSetting.tab = tabName;
        tabSetting.visibility = visibility;
        profileMD.tabVisibilities = new List<MetadataService.ProfileTabVisibility>{tabSetting};
        
        // Deploy the update
        List<MetadataService.SaveResult> results = service.updateMetadata(new MetadataService.Metadata[] { profileMD });
        if (results[0].success) {
            System.debug('Tab visibility updated successfully for ' + profileName);
        } else {
            System.debug('Error: ' + results[0].errors[0].message);
        }
    }
}

public class AssignAppTabPermission {
    public static void assignPermissionSet(Id userId, String permissionSetName) {
        PermissionSet ps = [SELECT Id FROM PermissionSet WHERE Name = :permissionSetName LIMIT 1];
        if (ps != null) {
            PermissionSetAssignment psa = new PermissionSetAssignment(
                AssigneeId = userId,
                PermissionSetId = ps.Id
            );
            insert psa;
        }
    }
}