Comment by muhammadusman

I moved to using Fastmail as my primary over 7 years ago and I still use it as my main email address but I had hoped I could get rid of my gmail but instead it became a catch-all junk inbox similar to OP's gmail. The main issue is that so many websites use Login in with Google as a way to sign-in that I just had to keep my gmail logged in most of the time.

So instead of "moving away from Gmail to Fastmail" it's more like "using Gmail and Fastmail" for me.