My bad, I was thinking about the Pro models' 10Gbps maximum and was looking for comparisons at that speed. I replaced what you wrote with the phone I had in my head!
For determining whether it's USB 2 or not maybe (and even then it might not be so clear cut).
For actual use the actual practical max speed is far more important. It would be useless if you wanted something better than USB 2.0 and it only did 1.1 times the USB 2 limit for example.
My girlfriend's Pixel 4a can transfer about 4x USB2's real world maximum. Just tested it.
USB 3 isn't new, it dates back to 2008. Every Pixel phone except the original Pixel 1 (USB 3.0) and Pixel 3a (USB 2.0) supports USB 3.1.