First thought: oh, huh, a self-hosted CVE generator. In seriousness, installing Roundcube on my own server circa 2006 was the cause of the first and only time I’ve had a server hacked. It’s probably improved since then or it wouldn’t still be around, but it put me off ever hosting my own email. The risks only get worse the further away you get from personal/hobby use.
I've used https://mailu.io . It works well, but your biggest problem is going to be getting over the spam filter hurdles of the email giants of the world. Even if everything is properly configured (including dkim / spf / whatever else they've added) your messages will get plopped in the spam folder.
For my current server I had to switch IPs a few times, until I got one that was not blocked by any of the major providers. Unblocking a once blacklisted IP seems to be practically impossible.
And hotmail or outlook.com just mark a lot of email as spam. I see it now as a problem of the recipients. Office365 just accepts the same emails, it seems to be a strategy of the free mail providers, to give their non-paying customers a worse experience.