If you only care about email (and calendar, I guess) Tuta is a pretty good choice. I’ve been using it for years and had only one problem very early on. Additional aliases are only available with the paid plan (€3 a month) however, same as Proton I believe.
I’m still on a legacy plan (which still feels like a really good deal despite some small concessions compared to the new plans) but yeah, even with the new prices it’s definitely worth it.
Also, while not strictly email focused but they have a blog with articles about various privacy related topics and news - it’s a pretty neat source of info, especially for those less knowledgeable about this stuff.