The only service we've ever had issues with is Outlook as they'll ban whole block for opaque reasons and we just escalate it to the provider and they sort it. We just moved two self-hosted mail servers to new IP addresses and there were only 2 lists to clear them from, which was a fill in form style automated process to resolve.
There's always SES (or other service of choice) as a backup for sending anyway if you notice something getting blocked. It's easy to switch to that for a day or two whilst you resolve an issue - though I must admit I think we only had to do that once in the last 12 months.
Maybe I'm breaking some kind of sysadmin code here and I don't realise it's a secret that self-hosting email isn't that hard? Am I supposed to keep up the myth that it is? :-) Any greybeards here please let me know!
Previously, I was also using Sendgrid as well. But they seemed to start doing the "growth at any costs" bullshit which for an email sending company means accepting and delivering spam. (Regardless of their PR/weasel-words these places use to deny it, that's what it comes down to). Thus lots of places now just drop all mail that comes from Sendgrid, no workaround.
When that happened, a friend pointed me to smtp2go, which I've used since personally and we now use at work. We haven't (yet) had anything blocked as spam (less than 10k emails sent a month though), so it seems like they've not done the "growth at any costs" bullshit like Sendgrid.
Piece of cake /s