FBKampfer
Banned
There would have been another round of fighting later on, but I believe Stalin would have gone for a Brest litovsk if offered terms (integrity of the Russian borders being prerequisite). Not based on the rumors that he was considering asking for one, but just that if offered, they didn't stand to lose anything the Germans hadn't already taken, and it offered a breather that, at the time, it looked like the USSR could have desperately used.You make it sound like defeating the Soviet Union is trivial.
Overall it would end up with Russians at the Reichstag, but it satisfies the requirement that UK gets out of the war.