The problem for Ukraine isn't lack of capability in the Russian command structure; it's the fact that Western passivity and stupidity has enabled Russia to fight on its own terms - a war of grinding attrition. In this type of warfare Russia has the overwhelming advantage of endless supplies of meat to throw into the grinder until such time as what little Western aid remains is entirely consumed. Then, because no more will be forthcoming (European NATO members having nothing left, the USA being in control of the ultra-right Republican Party that's overtly pro-Kremlin) sheer numbers will deliver a final costly victory.