I tried Proton, even paid for a year. But hot damn the Android app is garbage. So I've moved to Fastmail and I like it a lot. The app is snappy and I love that it has calendar, contacts, mail, notes, and files storage all in the same app. I used a custom domain with Proton so wasn't hard to switch to a different provider. Just wish I would've known how bad the mobile app was before I plunked down the money.
I've heard that. Boy does it need it. But I'll admit I don't like that their focus seems to be on introducing new products instead of making their existing lineup more reliable/performant. And not making many strides in the Linux world.