Wouldn't they have most of that just from customs/your passport? Not saying it isn't all rather dystopian, but, like, they have your ID as soon as you hit an airport.
Just transited in HKG, the gates are same but boarding at different levels. So you clear the security at a common area, get same PP checks done then go to departure gate which is one level above. IIRC Qatar etc are the same.
But PP checks do happen in both cases.
The false positive rate when doing this via passenger records alone is so high that airport law enforcement will generally only go out of their way to actively look for particularly interesting people.