I have it too, I know you’ve probably tried a lot to make it go away, but ‘Habituation’ really worked for me. It’s basically just pretending you don’t hear it and trying to ignore it until you don’t think of it. Sounds incredibly frustrating I know but just sharing my experience. I hope it gets better for you my friend.

There’s also a trick where you basically thwack the back of your head repeatedly that used to give me a temporary reprieve. It’s kind of magic, but doesn’t last long.