Some nuance:

If Google gobble up data about EU citizens then they fall under GDPR.

It doesn't matter that they don't allow EU citizens to use the result.

If our personal data is in there and they are don't protect it properly they are violating EU law. And protecting it properly means from everyone, not just EU citizens.

Actually, in case of Google it is, because they still do business within the EU.

GDPR is likely not enforceable if you have no presence in EU whatsoever, if you have no assets in EU and no money coming in from EU.

Anything Google does with data of EU residents is subject to GDPR even if that particular service is not offered within EU, and it is definitely enforceable because Google has a presence in EU, which can be (and has been) subjected to fines, seizures of assets, etc.

That’s a common belief, but it’s wrong. In principle an EU court could decide to apply the GDPR to conduct outside the EU; and in the right circumstances, a non-EU court might rule that the GDPR applies.

Choice of law is anything but simple. Think of geographic scoping of laws as a rough rule of thumb sovereign states use to avoid annoying each other, rather than as a law of nature.