https://tinyletter.com/mbutterick/letters/you-re-not-the-bos...
That's not even getting into international pressure levers.
I don't know that we've seen any of those kinds of actions yet, but they're clearly on the table if a company breaking the rules became a real "problem".
The thing is, if you're just completely avoiding doing any business with the EU, having any EU customers or users, and just not touching the EU with a 1000 mile pole and avoiding the GDPR in such a fashion - well, then there's no reason to go after you. The legislation has done its job.
In other words, the EU can attempt to extend its internet regulations over the rest of the world by implementing a China-style firewall. Well, we'll see if that happens.
Here’s a case example, BNP Paribas dealings with sanctioned countries. https://www.wsj.com/articles/bnp-agrees-to-pay-over-8-8-bill...
For example, that's what the US is using on Kim Dotcom.