Have you got specific examples? I can't recall this happening.
Some of it I agree with. Hate speech, disinformation, etc. but if google "owns" DNS than it's going to be the same story.
To take a specific service and say they haven’t is just naive.
Of course, this question would be silly under a dictatorship; the answer would just be "records have been suppressed." But we don't live in a dictatorship. Anyone in the US can use any DNS provider they like, even ones from outside the US. And anyone outside the US can use our DNS providers. So why would there be no evidence?
Mind you, I'm not necessarily arguing that Google wouldn't do this, if they were demanded to do so via a National Security Letter. I'm just arguing that you shouldn't conflate "no evidence that they're not willing to" with "already have in the past."
For IPv6 there is plenty of space and if you have a real use for more than a /48 then you can write up the paperwork for why you need so much space and get it approved, you don't need IANA, whether in Switzerland or anywhere else.