Going further east in 1942 if they hold Moscow wasn't a big challenge given that they'd hold the main rail hub of the USSR. The biggest problem with the 1942 offensive south was the dearth of rail lines, especially high capacity lines, to Stalingrad and into the Caucasus (plus of course the huge distances needed to be traveled, which were considerably further than from Moscow to the Gorki-Upper Volga region).
1). that assumes the Soviets don't wreck the Moscow rail hubs just like they wrecked the rail infrastructure in the west. It also assumes the soviets don't just wreck the lines coming out of the Moscow hub further down the tracks (Moscow hub is no use to the German's if it doesn't go anywhere).
2). Germany has still got a massive logistics problems, just from lack of resources. Plus unless every battle they then fight is right next to an (intact) railway line just having the trains doesn't help logistics as you still have to move stuff on from the trains. As you say "plus of course the huge distances". Similarly even if they capture an intact Moscow hub, and the rail system into the Russian interior from there is magically untouched, if they still don't have tracks to Moscow from their side it doesn't matter much. Basically for the resource strapped German forces you are talking about basically recreating the Russian railway system from scrap under constant sabotage efforts in the west and from Moscow eastwards likely red army pressure.
3). The amount of losses they had suffered just getting a few units close to Moscow (without taking it) were not long term sustainable, even if they take and hold Moscow without lots of losses, going further in just looks like 1942 and 1943 only worse because they'll be operating on even longer supply lines. Because the ridiculous thing is that bit of western Russia before Moscow, that huge bit of territory the scope of which just almost undid them by itself
is small compared to what they'd now face. Remember the German thinking was if they got to Moscow the soviets would already be beaten because their armed forces would already be destroyed on the way to Moscow. They weren't ever planning on fighting hard past Moscow, because Moscow itself was going to be the victory lap.
4). Holding Moscow isn't as easy as just arriving there and popping a panzer hatch in red square. It's a massive city of millions of people just securing and holding the civilians will tie down huge numbers. They're going to fight and resist, the red army are going to counter attack.
You kind of can, Strasserist Nazis were a thing. Hitler just purged dissent within the party pre-war, but there were still Nazis who disagreed with policy in the East vis a vis the Russian people, but Hitler blocked all recommendations and efforts to be less brutal toward the Russians and even build up Vlasov's army, same with the UPA that they had allied with for a while.
You kind of can't, as you just pointed out these "nice" nazis" weren't given any room to do anything. so the mere fact that a few still existed post night of the long knives really doesn't mean anything. This also buys into the old myth that the German armed forces were morally opposed to killing millions of Russians, but were forced to by Hitler and the upper echelons i.e they just need an excuse or slight change at the top to not be a key part of all the killing. But the reality is German armed forces were told to and didn't offer much resistance to doing so after the various Fuhrer directives came down. There's also the point that "strasserist" (itself a pretty broad term especially after the purges when we're really just talking about a diverse and eclectic group of individuals) might mean not quite as bad as Hitler but that still leave plenty of room for them to be bad in their own right and in terms of Russia.
Vlasovs army of Russian liberation is late war anyway at which point it's just a desperate German move to find more warm bodies between them and the red army because they're losing. The joke is the 'Russian liberation army' was even at it's for lack of better term
height, dwarfed by the numbers of Ostenheiten anyway. The Ostenheiten who had been mainly used for rear echelon security (and all that entails in occupied Russia) so really the opposite of the Germans being nice. Of course the irony is come 1944 they where mutinying more and more because the Germans are losing.
Really this idea that there was some grand white Russian army just waiting unutilised by the nazis is a myth.
