Nazi Germany was fighting a two-front war when it started Operation Barbarossa and was able to get to the gates of Moscow you're telling me that the British Germans French polish and many other nations unified won't be able to bring them down because of logistics I don't see it it's not like the Soviets to blockade Europe they'll be getting plenty of supplies
Eastern European winter can possibly delay the fighting but the Soviets will not be able to break through the lines like they did in our timeline the Coalition forces will be well supplied and there will be more soldiers you also have partisan forces helping you seem to fail to realize how many people hated Stalin and the Bolsheviks a socialist Fanny Kaplan tried to kill Lenin for his hostile takeover of the government you do realize the Soviets lost the elections to the Socialist and ignore the people's will and took over the country it might seem far away to you while reading this but this s*** is still fresh in a lot of people's minds
https://en.wikipedia.org/wiki/1917_Russian_Constituent_Assembly_election not to mention all the purges and crap Stalin did there is no red alert crap the Soviet Union collapses under the weight of the European coalition liberating the oppressed workers of the Soviet Union.