Regarding the figure of around 80% losses in a unit, isn't that fairly normal over a few months of fighting? There were similar, and higher, figures for some allied units after D-Day. Perhaps a better measure of unit-stress might be the availability of BCRs and periods of rest and retraining.
Wouldn't the unit be replenished by replacements in a conscript army where there's a constant churn of new youth coming through and former conscripts subject to recall on the states whim, where Russia and its army is concerned? It has the fifth largest standing army and third largest reserve in the world. Obviously, for the Uke's it is a different story but they've effectively mobilised the country by forbidding males of fighting age from leaving and having an influx of experienced volunteers from abroad (International Legion) and former domestic servicemen returning to the colours.
Yet...
Last week we were remarking on the Russian standard Battalion Tactical Group formation of 600-800 fighting men being committed to action as a unit comprising a mere 30-40 men in strength - a platoon-sized formation. So why are the Russians running out of men? Their losses across the board, as reported, seem to be pretty much four times the Uke's but their pool of bayonets, at least on paper, is somewhat vaster - albeit poorly-trained.
The Uke's seem to have far better battlefield trauma care and field hospital facilities and seem to be getting the lightly-wounded treated, rehabilitated and back into action quite quickly, whilst getting the more serious cases to the rear and into rehabilitation. The Russians seem to not fare too well if they get clipped which would affect the recirculation rate. Even so, on paper they have a large pool of (poorly) trained bodies to throw in. Unless they are suffering from mass desertions, lawyer-backed refusal to deploy and unable to deplete garrisons, say, along the Amur River lest the Chinese get smart ideas, that is...?
Edited to add: subsequent reply by Sadurian now seen.
Edited to add more: thanks to the Uke's Russia may have slipped or may be shortly going to slip a place or two in the standing army rankings.