Trying to avoid the landmines of blacklisting is really the biggest peril in all of it. I refuse to move a company I support away from GSuite to self-hosted, because I have a high level of confidence that just one person sending a lot of mail to another person outside the company could result in our domain ending up in RBLs, which is very difficult to reverse. Running a mail server in 2019 is not something I need the headache of.
And RBLs aren't that great. I visited this in January of 2018 [1] and in my case (where I do greylisting [2][3]but nothing else for spam) it wouldn't help.
[3] And yes, I do run my own server. It's just for me, so I have no issues with "customer requests" and I've been using the same IP address for about a decade (maybe more). Then again, I've been running my own email sever since 1998.
