i moved to mailinabox last year and it has been great. i can only encourage more people to try self hosting stuff and start from the simplest of things.
Currently hosting at home, but tossing up whether it would be better off on a VPS.
I'm not currently getting blocked by Google or Microsoft, and maybe that's because it's hosted via my home connection (and therefore not within a set of known untrustworthy IP addresses), but Mailu has an easy path to ensuring SPF and DKIM are setup, which add legitimacy to the email domain.
I've been testing with a domain name that I haven't used for email before, so it's a clean slate, though I'm not sure how much difference that makes in getting blocked or not.
No OP, but I’m using mailinabox on a linode vps for $5/month. The IP is in a range that doesn’t typically get marked as spam by default, and there are several checkers in place on the admin console to make sure that you’re dotting all of your “i”s and crossing all of your “t”s, from MTA-STS to DNSSEC. I do still run into problems from time to time, but it’s very rare these days.
Is there a documented reason to believe that DNSSEC is important, or really even at all influential, with deliverability? Most email origins, even the ones doing their own hosting, aren't DNSSEC-signed; if DNSSEC was a deliverability signal, most domains would be having problems.
Mailgun and others also have a free tier for relaying smaller numbers of email.
I've configured Postfix to use it for fallback if I can't deliver directly.
I use Digital Ocean and seem to struggle a bit delivering directly. 60 emails this month had to be delivered through mailgun since direct failed. Their free tier is up to 1250 emails per month.
Fellow mailinabox user here. I love how their system “just works”, and wish there was more support for getting mail servers back in the hands of the masses.
Something that I very much enjoy is that mailinabox comes with nextcloud installed, which it uses for its exchange activesync calendar. I can sync everything from my keepass database to contacts and reminders to my mailinabox across devices.