I used to self-host years ago but I've abandoned the idea now.
FWIW, with mox, I prefer not to rely on blocklists (centralized!). Incoming mail is first checked with reputation of the sender. This reputation is only per account. So one accounts junk-classification doesn't affect another accounts. Only for new senders, and without conclusive signals, would a DNSBL be used. The result is that you can keep communicating with folks you've been communicating with for years, even if their IP is on a blocklist.
I wonder if the large providers are doing something like this as well. I suspect many mail servers use a DNSBL early in an SMTP session.
99.9% of the time self hosting is fine. But then a critical business email is never received (like replying to an interview request or business proposal). The worst part is you never even know it failed to be received. The worst offenders are outlook.com and yahoo.com in my experience of self-hosting email for about 10 years. I stopped around 4 years ago after a critical email disappeared and impacted me financially.
Only way to guarantee your emails are always sent and received is to use a major email provider, sadly. Or hire a team to actively look after your domain and make sure large providers are not filtering your emails.
However, given my emails now are pretty much just for personal usage, I may look at moving back to self hosted. Greylisting is the superior approach to spam control imo and you can only get this with self hosted. Mox looks really great and I'll def consider it.
So... I couldn't email my family member at their work from my gmail. Not a big deal for me, but I know it impacted their ability to work with some clients and providers. And then... sure enough, they were getting spam from MS-hosted stuff (outlook.com, azure hosted stuff, etc).
He might have thought he was getting one over on google or something like that - I'm sure they didn't give a toss about it.
With MXRoute and my own self-hosted email, I'm slowly moving away from the big ones.
That's been the opposite problem for me. I can see my email leaving my client, see it hitting my SMTP server, and I can see Gmail accepting it. The client cannot find the emails. Not in their Spam folder either. I have no issues sending to my test Gmail account or my friends, but new people? Forget it. Google simply loses the email. I"ve tried to contact them to no avail (no surprise) and the usual answer I get from others is "well, just use gmail. nobody self hosts anymore."
That's why one ought to do ip warming on the ip and contact different big email provider to get the ip white listed. It is not impossible. Maybe ought to be a service to do all that bureaucratic stuff.
I promptly got approval for 50,000 mails/day!