I've cancelled my subscription yesterday, conveniently it was about to renew at the end of the week, so I have a few days to migrate from Proton, here's what I'm thinking of, but I'd love to hear what other people are switching to
Both are good options, but ATM the tuta protocol isn't standardized which means you are relying on tuta maintaining their favorable stance on privacy, unlike other providers which still have support for IMAP and pop. ATM if you go with tuta you are committing to both their infrastructure & client whereas most other providers you don't have to use their client.