Yeah, that official Intel product page is confusing, since it claimed "UHD for 10th gen", but maybe that's on purpose - I've seen reviewers and other sites stating that the UHD graphics in the 10710u is just the regular UHD 620; here for instance:
Benchmarks, information, and specifications for the Intel Core i7-10710U
www.notebookcheck.net
Also, I DO get acceleration, or at least it seems. I tried Handbrake with Quicksync, it does accelerate encoding significantly over software only. 4K60 video playback in VLC also seems to work.
It's weird.