Yep. We have tables that use UUIDv4 that have 60M+ rows and don't have any performance problems with them. Would some queries be faster using something else? Probably, but again, for us it's not close to being a bottleneck. If it becomes a problem at 600M or 6B rows, we'll deal with it then. We'll probably switch to UUIDv7 at some point, but it's not a priority and we'll do some tests on our data first. Does my experience mean you should use UUIDv4? No. Understand your own system and evaluate how the tradeoffs apply to you.
Nice feedback. Out of curiosity, have you made any fine-tuning to psql that greatly improved performance?
I have tables that have billions of rows that use UUIDv4 primary keys and I haven't encountered any issues either. I do use UUIDv7 for write-heavy tables, but even then, I got a way bigger performance boost from batching inserts than switching from UUIDv4 to UUIDv7. Issue is way overblown.