@Iisded If G has its forces placed to keep the R stack in WR, as it should, then trading Karelia, Ukraine and Caucasus. At some point G will capture Karelia in sufficient strength to hold it, but that is not the death-knell for R. Then R must block Archangel every turn to stop any tanks in Karelia reaching Moscow.
If G (or J) manage to hold Caucasus and start to build there, then the writing is probably on the wall for Moscow.
So my R stack will stay in WR unless any of the following happens:G get odds on me there. The recapture of Caucasus requires me to denude WR’s defence to a dangerous extent. R fails to block Archangel, necessitating a withdrawal to Moscow.
Against a poor G player R will gradually gain a sufficient advantage to start to use its mobile units (supported by sufficient infantry) to kill off any smaller invading forces without those mobile units then being at risk.
But these moves are what I do against my opponents. I taught all of them to play so their moves are constrained by my guidance. I do not want to pretend that this covers every eventuality that other opponents might present.