I too have self-hosted for decades, there was a brief period of annoyance where I had to set up SPF records long ago, but since then it hasn't been problematic AFAIK (not that I'm in constant contact with people on all the major providers).

However, a close friend and fellow ex-sysadmin who also has self-hosted since the 90s, has had some headaches in recent years. He upgraded his dedicated server at the same US provider I use, without attempting to preserve his original IP addresses.

He hosts email for his wife's small business, and with the new IP addresses has come a lot of problems. Her billing is performed primarily via email, when the emails get blocked, her income is directly affected. It's so bad sometimes I'd say it's straining their marriage.

This isn't at a disreputable hosting company. It's simply the reality of provisioning new systems receiving new ipv4 addresses inherently from a pool outside the pre-spamers-and-scammers-everywhere era, these addresses have passed through a dumpster fire of abusers.

At this point I'll never retire my dedicated server just to hang onto its IP address with a clean history I've controlled since the 1990s. Even if the machine becomes nothing more than an overpriced reverse proxy to somewhere else I run the real back-end on... the address has become the primary value.

So when advising people begin self-hosting, at least consider the reality of available ipv4 addresses they're likely to end up with. Even the reputable vendors have been used by malicious actors buying hosting with stolen credit cards and fake identities. We can't have nice things.