I’ve thinking about ditching my Protonmail email address with Posteo since I need IMAP support (because I hate using the Protonmail app) and honestly paying for Proton Mail Plus didn’t worth the money because they are pushing me to buy the Protonmail Unlimited but I don’t need all those capabilities nor would I use them and the best alternative I’ve found is Posteo and honestly I like it, I even got CalDAV support which I didn’t have in Protonmail, but personally I don’t know anybody who use Posteo, so I post this here.
I just ditched Proton Unlimited after moving to it last year from Google. The Drive app just never worked properly. Ended up going with Fastmail for email as I’m in Australia anyway and so far they’ve been good.