I haven't tested the 3.1 (my 3.0 works great), but I've recently acquired a couple of USB3.2 drives which are working without issue in the 3000 and 2000NXS2; they're the SanDisk Extreme Pro 256GB USB3.2 and a Sabrent Rocket 1TB USB3.2.
I'll leave the usual disclaimer; Pioneer DJ does not guarantee 100% compatibility with any USB drive. Functionality of one drive does not guarantee functionality of another identical make / model drive. Manufacturers are known to change the memory controller chip per availability or cost, and as a result, there is always a chance that a drive may not be compatible with the player host chipset. Recommendations or the results of another user may not be the same for you and your drive.