Lately I’ve been using Proton, it’s really comfortable, its interface and since I still have Google I don’t miss any notification, but I heard that Tuta is better, is it true?
The only complaint I have with this one is its interface, it is still web based, and it can be a bit uncomfortable
I used to be a Proton user (paid) for over a year, but I left them due to their lack of support/development of Linux programs.
I didn’t go for Tuta as I could not use Thunderbird or any client of my choice, felt even more of a vendor lock-in than Proton.
Then, I shifted to mailbox.org and I manage my own PGP keys.
Your choice depends upon what exactly you need.