I'm feeling exactly the same, I'm in a CBT Therapy group rn which feels double invalidating because everyone else seems to have the exact opposite problems.
I'm currently working through a book on Inter Familial Systems Therapy and it's a much better fit - it works by assigning personas to specific problematic thought patterns and talking the issues out with those personas. Way more validating in my opinion, as it's focused on being empathetic towards them and guiding them in a better direction.
More people do it than you might think! I sit in an office of 8, there's always someone either quietly beatboxing to themselves, doing minute long "uhhhrrmm"s or muttering movie quotes. There's an understanding that anyone who feels bothered by the stimming can put on their noise cancelling headphones lol