This is exactly how I feel, and now I'm not sure where to move because I have 8 domains configured and services like ProtonMail want me to pay them for every domain (which just makes no sense to me, I can't figure out how the code that makes this a costly problem looks, my guess is it's a money grab tbh).
Sure I don't often use them all, but it comes in handy at times to be able to quickly use a different domain.
Been looking at Tutanota, but not sure how I feel about being required to use their clients.
Any other good suggestions?
