A quick search indicates "Up to €20 million, or 4% of the worldwide annual revenue of the prior financial year, whichever is higher" https://www.gdpreu.org/compliance/fines-and-penalties/
Google has come out of antitrust cases relatively unscathed. They've even violated GDPR itself once before explicitly, and got out with a 57MM$ fine. This case won't be any different than all the other times that Google has blatantly violated laws and walked away with a slap on the wrist.
I would be very very very shocked if the EU actually managed to touch Google. I welcome and hope to be proved wrong.
If the law literally doesn't work because of reasons, then that's just systemic corruption.
It's a lot of regulations that can be worked around and the fines are hard to and rarely enforced. There are a bunch of poster children of GDPR fines that make it seem like it's doing a lot but the principal abusers (i.e. Google) just walk away with a light slap.
It needs the ability to be enforced, and I think this much should be obvious to lawmakers -- a law that can't be enforced well is useless.
That's why I'm calling it privacy theater. It's the EU saying "look what we did!" but in practice it doesn't really do much without enforcement that still does not exist both at a national and global scale.