My 9yo daughter has a tablet with family link, so I can monitor what apps she wants to install. As the garbage games are mostly at the top free, she keeps asking for games that I reject, in most cases because it's riddled with ads.

Did you ever consider using this as opportunity to educate your daughter about ads in general, how some games try to push adds to get you to do something, and also how some games have game mechanics trying to push you to do specific things, and then just let her figure out if those games are worth playing, or not?

She's definitely old enough - I had that discussion with my daughter when she was 5, we have an agreement that we limit the number of games installed on her phone - and the kind of shitty game you're talking about typically gets uninstalled again pretty quickly.

In a few years she'll be able to install stuff by herself - if you never explained to her what and why games/apps are doing she'll not be ready to deal with that, and it'll be out of your control.