What is the ruling on saying: "O Allah, forsake..." and is it permissible to associate the attribute of forsaking (al-khidhlān) with Allah - the Mighty and Majestic?

There is no objection to the phrase "Allah grants victory to whom He wills and forsakes whom He wills," because it is Allah, the Exalted, who grants victory and forsakes, as stated in His verse: {If Allah should aid you, no one can overcome you; but if He should forsake you, who is there that can aid you after Him? And upon Allah let the believers rely.}