Pull them all back and see what happens. If Germany buys transports for a sea lion attack on London, then go back to Amur and then down into China and help them take and hold Kiangsu and maybe even Hongkong. You might prevent a Pacific VC win if you are lucky. Don’t forget you can mobilize new Chinese infantry on top of your Russians.
If Germany does not buy transports and masses troops along the Russian border for a G3 attack, then you better start marching them all West.
However, if Germany launches Barbarossa on G2 they may be too little too late anyway. A German attack could start out as a mass of tactical bombers, armor, artillery and infantry in Hungary that moves East 1 territory per turn. Meanwhile 10 mechanized infantry are built each turn in Germany to replace infantry losses. The mechs also protect the tactical bombers in East Poland. The schedule is East Poland G2, Belarus G3, Bryansk G4, then Moscow G5 onward. Ukraine probably evacuates.
So Germany is attacking Moscow G5, but there are 6 Far East troops in Samara and another 14 units in Novosibersk. Those replacements make it possible for Russia to hold on as Germany batters Moscow G6, G7, G8, and just maybe the Germans will finally run out of infantry and die.