Deliverability issues for personal servers are emphatically not a myth. One reason I moved off self-hosting mail a couple of months ago, after 17 uninterrupted years of doing so, was because of perennial problems with deliverability - and Gmail, while bad, wasn't even the worst; some large providers (glaring daggers at you, Microsoft) make it effectively impossible even to understand why mail is getting blackholed, much less do anything about it.
(Fastmail, in case anyone is wondering. $50 a year, and there's nothing I want that they don't do.)
(Fastmail, in case anyone is wondering. $50 a year, and there's nothing I want that they don't do.)