If you think PSG and City have spent over a billion on transfers and all of it has come from their sports revenue - then I am, respectfully, going to have to disagree.
Of course, the fact their owners are from those countries brought them sponsorship.
However, the work of UEFA is to put a fair market value on those sponsors. Not to ban them completely. And this is what UEFA did and led PSG to sell players. What do you want UEFA to do ? We all know that the reason why UEFA can't go further is that the basis of FFP is shaky and the sheiks have threaten to go to court if UEFA pushes too far. FFP has never existed in football before and can be challenged legally. This is why UEFA introduced settlement in their rules. To find some kind of agreements with the clubs that will accept a softer punishment and don't face full battle.
So far, the only clubs that have been banned are the ones who have trouble to actually pay the salaries, transfers fee. Lot of clubs from East Europe, Turkey. Not the clubs that are too rich due to their owners.