Who is responsible for the authenticity of Google's ads?

I'm searching with Google Xbox Series X. There are three ads here. Are the ads here all legal and genuine? Who is responsible for the authenticity of the ads? Is it possible that the ad is bogus and i get scammed into buying an Xbox and i can't get my money back?

If you don't use advertisements, nothing can happen.
I prefer to choose my providers myself.

Yes, it can happen, advertising is one thing, then ripping off customers is something completely different.