Very very sad that the adaptive subdivision is touted as a Blender feature but unfortunately it's a Cycles feature.

Always nice to see these updates though, Blender has really come a long long way.

It might be possible to reproduce the same effect in EEVEE using geometry nodes. I know people have done that for automatic level of detail work. That being said, IDK if subsurf as a geometry node will take a non-constant number of iterations.