Any small-to-medium paid email hoster. Because if not paid, you are the product. And large ones usually want both, your money and your data/advertising.

I use proton and it’s been solid

I use mailbox.org, and it's been good. I used tutanota for a while, but the fact that I couldn't use any email clients (they have their own now I've heard) made me switch. It's also why I didn't go with Proton, since you have to pay the $10/mo plan (I think) to do it with them.

Proton and Privateemail through Namecheap.