I don't mind paying for email if it's actually private. One advantage I found to using Proton Mail instead of my self hosted email server (other than the obvious convenience, config, maintenance, blocked port 25, IP reputation so you don't end up in spam, etc) is that the more people start to migrate off of Google and onto Proton, the more emails between Proton users will be E2E encrypted by default, so it's one of those "the more users, the better" kinda things.
Same with Tuta. Even though emails between a Proton and Tuta user aren't E2E, it's still a net benefit for everyone if more people switch to these private solutions.