Just now went down this Rabbit hole, looking for real data to contribute to various threads here.
Best answer I could find on the internet (Wikipedia?) was 136 “Battalion Tactical Groups” (BTG).
Which was the kind of number I was looking for.
Background: I was a late cold war (1980’s) Army Intelligence Analyst, and developed/have an interest in Soviet WW II Order of Battle Issues. Thru the end of the Cold War. Most of the unit Wikipedia pages I have looked at trace the descent of Russian/Ukrainian/Belarusian Military Units to their WWII/Cold war ancestors, and agree with my (Late cold war) information.
Knowing the numerical order of battle strength of the Soviet Army in the 1980’s, A total of 136 (?) Brigade/Division flagpoles, fielding 136 BTG’s is about right for the (current) Russian Army. Given the state of the Russian economy and society, the ability to mobilize significant numbers of additional useful units is dubious. Reminds me of the American “Broken Army” of the 1970s.
So how are the Ukrainians doing? Well, first we would need an actual count on the number of BCT’s committed to the operation. Then account for losses. Don’t be afraid to “count on your fingers”!
Which is left as an exercise for the student.