Had no problems at all self-hosting for two decades; then a provider went bust and I lost my static IP block, and with it its two decades of reputation.

I still self-host, but now I cheat for deliverability: route the problematic destinations (I'm looking at you, Outlook) through Amazon SES. At a few cents for five-figure numbers of emails, it's as close to free for personal/vanity email quantities as it gets to have someone whose full time job it is to make sure outgoing mail stays deliverable on your side while still keeping everything else under your control.

One thing to note is that Amazon are not very good at keeping amazonses.com up to date, so despite including it you can't set DMARC to hard-fail SPF or you will have mail bounce days.