I've been using Fastmail for years now to host emails for my domains. Works like a charm. Maybe worth for you too.

recently i was helping a a friend purchase a custom domain, and signup to a email service; even though i use fastmail, i was surprised to find proton was like 3eur per month (fastmail is 5eur). when my renewal expires, i will probably switch to proton - for 10eur the features are really good;