ONe precondition of an existing Kaiserreich is that Germany had won (or at least not lost

) the Great war.
So you can assume that OTLs Brest Litowsk peace stands.
You might get a free Ukraine (Soviet free that is - dominated by the Reich is not fully free

)
Thus the Soviet Union is at best much smaller than OTLS SU.
I assume that Germany props up an independent (still German puppet) Poland having about the same eastern border as OTLs Poland between the wars.
So Germany haas (at least 2, 3 if you count an possible still existimng Austria Hungary) allies for a war against a Soviet Union. In addition the starting lines for a German Soviet war would be further east.
England and France would not be Germanys enemies (probably) if GErmany would fight against the Soviets - or at least they woudl be less powerful compared to OTL.
Basically the Soviets would be pushed very hard TTL and the Push (assume it staarted the same time as OTL would reach further east. So its likely that the war would be over sooner - with a German Victory...
Heil die im Siegerkranz - music on.