True but it’s unthinkable that Uk will be neutral while Russia and Germany fight
Why ?
[it's not hard to POD this ... instead of keeping their Pact secret, Hitler and Stalin leaks their deal over Poland ... France & Britain step back from the 'guarantee' to Poland when faced with declaring war on BOTH Hitler and Stalin ...
EDIT why both ? because Hitlers and Stalins forces invade simultaneously ..
Then Hitler, instead of stopping and turning west, just rolls on through Poland and straight over the Red Army in October 1939 ....
Britain would, I suggest, be only too happy to watch the Nazi's and Communists bleed each other dry .... ]
SO - what happens then ?
Given how the RedArmy performed in Finland, before the winter stops play, the Nazi's would be half way to Moscow (advance limited only by their logistics) .... Why Moscow ? because the Nazi attack consists of a single thrust through Poland ....
Nazi success in France (which came DESPITE the 6 month 'phony war' during which defensive preperations would have been made) suggest that the early war Blitzkrieg success would work just as well against the Soviets ....
In the spring of 1940, the Nazi's advance will continue but still be slowed by logistics problems (and consolidating their gains) ==
If the Brits (& French) are sitting this out, they might be willing to sell arms to Stalin (or even Hitler) under 'cash and carry' terms, but this takes time to get going (and even longer to feed into the front lines). As does the preperation of defences .... (OTL 6 months of 'phony war' defensive preperations didn't make much difference to the speed at which the Panzers reached Paris - the Soviets would have maybe 2-3 months and that only in winter)
Is it ASB to suggest the Panzers could be in Moscow by end of 1940 ??? (instead of Paris ?)
Plus, if they do, would Stalin come to terms ??