Genocide refers to a People (race, kind, tribe, family, etc.), not individual people. The group is a concept, and 'killing' it doesn't have to involve the biological death of the group members. That's part of what the linked resolution is trying to say.
For example, you could go sterilize every member of an ethnic group, without killing - causing the biological death of - any of them. None of them will be able to have children, and as they die of old age, the group disappears. That's genocide.
Another example would be to forcibly separate all the members of the group and prevent them from engaging in the lifestyle associated with membership in the group (e.g. style of dress, music, food, language, worship, etc.). Over time, perhaps generations, the people basically give up trying to do any of these things if they even remember what they were. They have no group cohesion, so the group has essentially disappeared. No need to directly cause any biological death. The argument is that if this is done intentionally, it is also genocide.
Genocide as a concept is about ending the group, not specifically the individual members. It's definitely true that you can end a group by killing all its members, though.
You agreed with me that genocide is more expansive than "we're directly killing people". For the sake of argument, let's assume the allegations are true: what would you call that?
Taking an angle like "well, lets assume these things are true, THEN can we accuse China of genocide" is basically what the media did for 5 years on this topic.
My point about the assumption was to get you to agree that if these things are happening, we know that it constitutes genocide. At this point I don't care if you agree or not.
And it's very easy for me to believe that rates of childbirth and hence violations are higher for subsistence farmer populations than urban workers, because that's true everywhere. Uyghur population grew a ton between 2010-2020, 3 kids per couple is net growth.
Lastly, no, there's no such thing as a "technical" genocide on a points system without some massive crimes against humanity that would drop anyone's jaw, and those things are hard to hide. It's not like you make a couple of technical errors and, oops, genocide even though the population is substantially fine and economic reforms are working.
The only thing this does is cheapen the word. In the past genocide was something serious. But now it includes activities that are simply upsetting.
The word is attached to the intended outcome, not the specific actions taken to achieve it.
Using your example, if some ethnic group changed how they dressed it would be genocide.
That cheapens the word. Change in dress is not as severe an outcome as buried in a ditch with a bullet in your head.