I ran some numbers by GPT-5[0], and for the scenario of generating 10k UUIDs in one ms every 10ms, over three years, it came up with a 0.0025% chance of collision for UUIDv7, and a 0.000000084% chance for collision with UUIDv4.
I checked against my notes, I see about the same numbers using the `n**2` taylor series approximation. I missed that the probability of `>=1` collision is about the same as exactly one collision, but I suspect that's quite reasonable as this scale.