I think that, while true, that's a different matter. The inability of the Russian Air Force to establish air superiority is not necessarily related to dogfighting losses. As far as I know, Ukraine currently doesn't have much of an air force either.

I don't think Russian combat airplanes are being shot down with "nerf guns" either. For whatever reason, they haven't been able to establish superiority, but how does this relate to dogfighting skills?

A big factor is Ukraine still had a number of Soviet made S-300s and older Buks. Those things are very effective and can shoot down even modern aircraft, including Russian ones.

And remember, Ukraine is the largest country in Europe and the most armed and well trained. They are not Iraq or Vietnam.

Soviet air defense seems to be quite effective against soviet aircraft. I think Ukraine had a decent stockpile of that equipment, but they also got shipments of similar soviet made equipment from neighbors.