Which privacy-respecting email provider can you recommend? It seems that the following three are the best options:

- tutanota (0€ / 12€)
- posteo (12€)
- mailbox.org (12€)

Do you have any experience with them?
What do you think about a hosted email service with your own domain?

I'm trying to improve my email setup once again and need your advice. My idea is as follows:
- 2-5 users
- 1 (sub)domain per user with a catchall
- users need to be able to also send from <any>@<subdomain>.<domain>
- costs up to 1€ per user (without domain)
- provider & server not hosted in five eyes and reasonably privacy friendly
- supports standard protocols (IMAP, SMTP)
- reliable
- does not depend on me to manage it daily/weekly
- Billing/Payment for all accounts/domains at once would be nice-to-have, but not necessary

I registered a domain with wint.global the other day and I actually managed to get this to work, but unfortunately their hosting has been very underwhelming.. the server was unreachable for a few minutes yesterday not only once, but roughly once an hour, and I'd really rather be able to actually receive (and retrieve) my mail. Also their Plesk is quite slow. To be fair for their price it's more like I pay for the domain and get the hosting for free, but I digress..

I am also considering self hosting, but realistically that means running it on a VPS and keeping at secure and patched, which I'd rather outsource to a company who can afford someone to regularly read CVEs and keep things running. I don't really want to worry about maintaining servers when I'm on holiday for example and while an unpatched game server is an acceptable risk, I'd rather keep my email server on good shape.

So in the end the question is: Which provider can fulfill my email dreams?

My research so far:
1. Tutanota doesn't offer standard protocols. I get their reasons but that also makes me depended on their service/software, which I wouldn't like. Multiple domains only on the business plans.
2.With Migadu I could easily hit their limits of incoming mails if someone signs up for too many newsletters and I can't (and don't want to) micromanage that.
3. Strato: Unclear whether I can create mails for subdomains. Also I don't like the company for multiple reasons. However I can access a domains hosted there and could try...
4. united-domains: Unclear whether I can create mails for subdomains.
5. posteo: No custom domains allowed.

I'm getting tired.. *sigh*