I did a debloat on my Samsung and applied a patch, I didn't see anything come back. I can give better info if I decide to install the beta which isn't available yet.
Not usually. Carrier bloat tends to, but oem bloat typically doesn't.
Mind you, like most people, there's a limited sample size. It does include devices of other people, so it's not just the dozen or so devices I've had myself, but there's limits to what one person can speak for.