Something that has not really been discussed here thus far is the implications of the Russian invasion in terms of its effects on Russian national security; I.E. the material losses on Russian military forces.
The Russians are dedicating large amounts of munitions, cruise missiles, and other disposable systems to the Ukranian front which, although can be replaced cannot be replaced very quickly leading to what I can assume will be scarcity in these items for atleast a year or two if the conflict further escalates and the Ukrainians continue to hold out.
Further more Russian ground forces are taking larger than expected losses in armored forces and aerial assault units [I.E. Helicopters] which, although aren’t the most advanced units in service that are being deployed, will weaken over all military positioning at the end of the conflict. Assuming that they replace the losses, even if they pull existing tanks and vehicles out of reserve it require major modernization and will take time; Russian industry is not comparable to that of the Soviet Union, and their losses are already in the millions dollars.
I could be wrong however my take is that the losses the Russians are taking in their war with Ukraine is overall going to put further strain on their forces where it is not needed.