Agreed, I left Fastmail for Proton and am very happy with it. It improves/changes in fits and starts sometimes, but support is always great and overall I am happy with the usability, direction, pricing, etc.
I do wish ProtonMail handled labels/folders as one unified model like GMail does, it's so much simpler and more ergonomic. But I imagine hoping for a data model change like that is probably a pipe dream.