The ruling on praying behind an imam who is an innovator

Question:
May Allah reward you with good and do you good. You are asking for your opinion on the prayer, and on what happens when someone introduces religious innovations (bid'ah) in the prayer, in the supplication, and in other things after the prayer, such as his consistent and continuous adherence to supplication after the 'Asr prayer, and his adherence to the qunut supplication in the Fajr prayer. Please inform us. May Allah reward you with good.

Answer:
This is a matter of sincere advice. One should explain to him that these characteristics and these dhikr (remembrances) in this form are not established in the texts, and that it is obligatory for him to abandon them. If he complies and follows the Sunnah, praise be to Allah. If he does not comply, then he should strive to replace him with an imam who follows the Sunnah; he should strive to find an imam who follows the Sunnah.
As for if he prays behind him, and the only innovations he has are those mentioned by the questioner, then the prayer behind him is valid, praise be to Allah. Even if he recites the qunut in the Fajr prayer, or if he uses dhikr after the prayer in a form that is not established in the texts, this is a bid'ah (religious innovation), yes, but it does not reach the level of invalidating the prayer. One prays behind him, praise be to Allah. Yes.