As a guy who's blog and email consists of .xyz domains, I can only say two or three times in ad many years has it ever been a problem (that I'm aware of, at least), and then it was a website not letting me create an account using it for email.
Same here. My DKIM headers are signed by a well known and respected email provider. I assume if you self host the results are gonna be wildly different.
Sometimes I send reminders from my xyz domain to my corporate email accounts (which tend to have a rather aggressive filtering) and everything seems to work fine.
I suspect I'm either lucky, or something.