Yeah, agreed with the other comment here on mail.

I've tried their VPN, Calendar, Protonpass extension, etc.

VPN gets a 5/10 for me. I prefer PIA for speed, reliability, and streaming. (Also dedicated IP optino.)

Calendar gets a 1/10 for me. I don't use it, it was too hard to figure out in terms of UX.

Proton Pass gets a 9/10 for me. Easy, quick, importing all my passwords into it was fast. I wish it had a standalone app with local storage or something.

I use several custom domains for mail and have appreciated having the option to have it all in the same inbox. I wouldn't personally compare it to Google one-to-one, but it's excellent at mail.