I installed Mailinabox [1] four years ago. There was one annoying upgrade, whose process needs to improved, but outside of that haven't touched anything. Only a couple of random domains where email delivery has failed. Otherwise, it just delivers to all the big providers.
That annoying upgrade is the reason I’m planning on moving to Stalwart[1]. I’m still on the old MiaB version and I’ve always been interested in JMAP (which Stalwart supports)
[1] https://mailinabox.email/