Kids these days with their containers and their pipelines and their devops. Back in my day…

Don’t get me started about the internal devs at work. You’ve already got me triggered.

And, I can just imagine the posts they’re making about how the internal IT slows them down and causes issues with the development cycle.

Yep. I’ve hosted my own mail server since the early oughts. One additional hurdle I’d add to you list is rDNS. If you can’t get that set up, you’ll have a hard time reaching many mail servers. Besides port blocking, that’s one of the many reason it’s a non-starter on consumer ISP.

I actually started on a static ISDN line when rDNS wasn’t an issue for running a mail server. Moved to business class dsl, and Ameritech actually delegated rDNS to me for my /29. When I moved to Comcast business, they wouldn’t delegate the rDNS for the IPv4. They did create rDNS entries for me, and they did delegate the rDNS for the IPv6 block. Though the way they deal with the /56 IPv6 block means only the first /64 is useable for rDNS.

But, everything you list has been things I’ve needed to deal with over the years.