Is there somewhere to see if something was a purposeful design change, or a bug? I'm upgrading a few things from Umbraco 13 to 14/15 and there are quite a few missing features, but maybe that's intentional

The Umbraco 14 release page on Our lists a few things that were missed/not ready when it was first released, but this will be slightly out of date now https://our.umbraco.com/download/releases/1400

Hmm, I would guess bugs then. I'll look into it, and report / fix some