Just remembered something that's very much in Xbox's favor over PS4- generosity with in-box codes.
Basically, if you buy a disc game, and there's a download code in the box for some DLC or cosmetics or what-have-you, on the PS4/Switch the code works once & that's it. Buy a used game, get a useless code. Not so on Xbox! The codes are tied to the game, so a code can be used again by a secondhand purchaser. No reason to fear buying used games & missing content- if you've got the code, you're good!
I've never seen any official statements on this, so I suppose in theory I'm wrong and it just so happens every used Xbox One game I've ever bought had an unused code in it... but that seems unlikely to me.