You wouldn’t be wrestling with this if nothing real was happening inside you.
The devil wants you to believe your prayers are fake. If he can convince you that everything you say to God is hollow performance, he’s won half the battle before you even realize there’s a battle going on.
Talk to God the way you would talk to a parent, messy and honest, without a script. Tell Him that you’re not sure anyone’s listening, and ask Him to change your heart, because you can’t manufacture that part yourself.