@einarpersson get a VPS, setup dns records, one of the many hosting managers (so no cli to create accounts), and maybe some rely provider to avoid delivery issues.
Your server will be the one sending the email, the rely will only stamp it as trust worthy so Google, Microsoft, etc don't block it.
And away you go.
The final step I would recommend is to switch to an email client like Thunderbird, Evolution, etc, via IMAP so you avoid WebUI
If you want ClaDav/CardDav a simple Nextcloud will do.