Define what you mean by Soviet defeat. Hitler's plan AA line was not feasible, but something along the lines of a Brest-Litovsk is not outside the realm of possibility...provided the West is not involved in the war.
Not if they attack in 1942. The Soviets were able to outproduce the Germans after losing a ton of resources and manpower in IOTL's 1942 without assistance from the Western Allies. ITTL, the Soviets will have suffered much less manpower casualties (while inflicting much greater manpower casualties on the Germans to boot) and be in retention of a lot more of their natural and industrial resources to boot. That translates into even greater production achievements then they achieved IOTL and what the Germans can possibly manage given the blocks they still face in material and manpower, not to mention their still poorly mobilized war economy...
The earlier the Brits start to defend against it.The earlier they start the night bombing
Ah, I see the ASBs magicked away British mine-sweeping capability.being bottled up by air deployed naval mines in the Mersey,
Well, since the Germans are apparently not making much effort to bomb Britain during the day ITTL...Then there is opportunity cost; what is Britain not producing to make night defenses?
So long as Britain survives the summer of 1940, then the US perception of Britain is going to be "the Brits stuck it out!"Without the BoB to rally the US public to the cause of Britain, there isn't going to be the same sort of support.
Which wasn't much of a big part of said story in the first place.Without that moment, rather a start to a blockade, then the US public doesn't have the romantic story of US pilots helping the British in their hour of need,
Instead, they get the story of the evil Germans trying to starve British civilians via blockade.nor do they get the story of the evil Germans bombing British civilians in terror raids
Which matters for nothing as far as shaping public perception goes.(Liverpool is a legitimate military target, as was Hamburg when the British started trying to bomb it in 1939).