Given that the Russians have just a few of their aircraft and not much more coming then it would make more sense to ask “Who cares?”.
OTOH, the Chinese aircraft should make a target rich environment for the F-35.
I live out near Nellis Air Force Base and F35 fly over all the time... I’ve always been in to airplanes and I always watch them (all types) and the F-35 does seem to have a distinct kind of Snappy (bee like) performance in their maneuvers