I also moved away my domains and the ones of the hackerspace I manage, mainly to:
- infomaniak (Switzerland): a bit too pushy with extra services, but not bad
- openprovider (NL): more geared towards bulk users, have to prepay (min 20€), but okay so far
- aruba: meh, but free mailboxes are nice
I also use Migadu, they have been great so far!
desec.io for DNS, also great and supported by Traefik for DNS-01 ACME challenge.
I use kanidm with oauth2-proxy. No issues so far, it was pretty easy to set up.
Note that the connection to kanidm needs to be TLS even if you have a reverse proxy!
EDIT: currently using 80MB RAM for two users and three Service Providers.