I can get PiP from shorts 100% just tested it (At least in MIUI, maybe it depends on the implementation)
What you're describing is a bit different(It's probably implemented like this because old videos that weren't initially uploaded as shorts were absorbed into shorts if they fit the correct criteria)
Is MIUI Xiaomi’s fork of Android or something else? I had to look it up so I’m half guessing here, but what I wrote is for iPhones and iPads. I don’t know how different YouTube is on Android but it was my impression they kept the implementations pretty close to feature and behavioral parity, but I haven’t used an Android phone full time in almost 8 years.
Yes, Xiaomi's layer on top of Android (Wouldn't call it a fork though, that has different implications)
As far as I can tell YouTube itself tends to be pretty similar, but features come first for Android, I think PiP for shorts is out of beta in Android, but as you mentioned just getting tested on iOS
