That isn't how UBI is advertised. If it was, it'd be no different to existing welfare systems and there'd be no need for any such name as UBI.
Of course, you can play silly accounting games in which you take $100 and give back $10 and say "look, you now have $10 in guaranteed income", but such word games have no merit and can't justify the claim to change to the economic system.
This is exactly how it's advertised. I have no idea where you've got the notion that UBI is about printing an extra $X for everyone, because it was never about that.
It was always about that, but I'm very curious what you think it's about. Because taxing someone $X and then giving them some of that money back as $Y is just word games - it's exactly the same as taking $(X - Y). We have that system already. If UBI just means higher welfare spending then call it that and stop running pointless trials.
Of course, you can play silly accounting games in which you take $100 and give back $10 and say "look, you now have $10 in guaranteed income", but such word games have no merit and can't justify the claim to change to the economic system.