Jayson Smith writes:
What I mean is that I'd love to find a good, reliable smarthost I can direct my SMTP server on my VPS to use.
You could try some of the services listed here: Hosting: https://wiki.list.org/COM/Mailman%20hosting%20services Consulting: https://wiki.list.org/COM/Mailman%20consulting%20services They might have a better idea or offer exactly the service you want.
Otherwise, I think you kinda have to move your VPS to the service you want to use, and on top of the monthlies for running a server they'll charge you for email volume. AWS SES for example is 10,000 emails for $1 billed monthly, and there's a throughput charge as well but that too is probably negligible unless you're mailing videos. They do promise an IP with a clean reputation and they bonk your neighbors (and you) automatically for sending more than a tiny amount of spam, so I'd expect it to stay that way. FWIW ....
The real problem I'm seeing is that seemingly within the last few years, at least some VPS providers (Linode and Digital Ocean for sure) have started getting entire IP ranges put on blocklists.
This is nothing new. Effort-minimizing admins have been blocking whole netblocks for well over a decade. I think one new aspect is that non-admins have borrowed the technique of mass-reporting to try to shut down all aspects of an individual's or organization's Internet presence. I wouldn't block at the SMTP CONNECT level based on IP or domain alone for the reasons you give for running your own smtpd, and I doubt Google or Microsoft do. But I know a lot of admins who do.
I don't know what to do about it. I think my own server at my university got on Microsoft's bad side once, but it got better fairly quickly. I did contact Microsoft but I don't know if it had anything to do with getting off their blocklist, the only reply I got was a 'bot saying thank you for contacting Microsoft, check this link. I don't think they have their best minds working on the problem. Instead they get customers by being too big to block, is my guess.