Wanted to share that I also had intense anxiety/depression well into my thirties but was able to finally sort it out a few years ago.

I think your phrase "learn how to relax" is spot-on. I was chronically under-slept and chronically over-focused on school, university, career, side-hustle(s), etc.--without much great effect I might add. My brain was so wound up from a decade-plus of hyper-vigilance that I had actually forgotten how to relax.

Obviously, I am not you and n=1, but hopefully it is encouraging to know that you might not always need to drown it out.