I use WWII Russians and control markers for Bolsheviks. These are controlled by the CPs, but cannot attack outside original Russian areas. Some sort of Siberian railway track to represent the arrival of Allied (i.e. anti-Bolshevik) forces from the east.
Something else I’ve experimented with is the release of POWs; if the war with Russia ends, G & A get a number of infantry to represent the release of prisoners held in Russia. This can be extended to any power being knocked out of the war.
My main change is that collapse is based on national morale, based on casualties suffered & bombing raids on the capitals as well as losing battles and tt. Its fairly obvious that collapse based on income levels favours the CPs too much.