Have you tried to use your GDPR rights and complain if they were not delivered? You are most likely get a template response, completely irrelevant to your complaint. Then few more templates when you try to "escalate" and finally you get no replies. That's how those big companies are serious about GDPR. Then if you try to complain to one of the body responsible for GDPR they'll likely say if you don't like the service, delete your account and no further action will be done. GDPR is one of those all sizzle but no stake.

Article 79 gives the data subject legal standing to bring a civil lawsuit against the data processor.

It's been the case before GDPR that you had to at least threaten legal action to make corporations behave. Freedom of association does typically mean that a human can just ban you from ever being their customer again, but that's IMO an important freedom. The monopoly ISP in your municipality doing the same to you does not seem ok, however. And it might not be reasonable to ban ownership of a Google account that's used exclusively for "Sign in with Google".

But these articles are largely toothless when it comes to big corporations. I am aware of only one case running against Facebook in the EU.

Then it is unrealistic to expect that an average individual will have money to sue the data processor, as the cost is out of reach for most of people.

Good to know. But he’s in California.

I believe Google deletes your data fairly quickly after they decide to ban you, so best get that GDPR request in fast.