The most likely victor of the chaos following a successful assassination of Hitler would be the SS.
The conspirators in the Wehrmacht and the civil bureaucracies were too small in number to
gain control quickly. The SS had been building a State within a State since the late 1930s and had
their own parallel bureaucracy serving all the functions of old line pre-nazi governmental organization.
With Hitler dead they would have moved swiftly against the Wehrmacht, the civil bureaucrats and the Party.
They probably would have almost completely in control by that point in 1944 anyhow if Heydrich hadn't
been killed, his death delayed a process of take-over that he and his young technocrats had been
assiduously working towards. His death also strengthened the positions if the Party Old Guard
and Gauleiters against his young professionals who had openly opposed the 'wasteful' deportations
and exterminations in occupied lands. Along with the general corruption and and simple stupidity of
most of the Party faithful who were made Gauleiters and assigned control of the various occupied zones,
no matter how badly those idiots screwed up Der Fuhrer always backed his old comrades.
These young SS technocrats saw it all as a terrible waste of labor resources, to these guys spending
money for transportation and extermination was pointlessly wasteful when one could just work them to death.
Heydrich's death meant that many of the more vocal of his young lions were shunted off into positions
where they couldn't do any harm, but they kept working on their plans. Many of these folks were
also vocally opposed to the whole notion of colonizing the East, they found the Nazi Party fantasies
of a massive continent-spanning Germania populated with rosy cheeked farmers tilling the soil of
the conquered lands ridiculous in the extreme.
Sure take it over, get the resources, put the existing peasants to work as slaves on the soil, but live
there? What the hell for? They wanted to live in a modern technological German state, not some
19th century Volkish fantasy of peasants in lederhosen tilling massive Baronial estates.
So by the time of the assassination attempt, while many of their plans had been delayed, they had still
managed to build the mechanism of a complete new government, down to the local level, so you kill
Hitler, the Party structure is in disarray, the Wehrmacht is in disarray and the civil bureaucrats are
sitting there waiting to see what happens, guess who would be perfectly placed to step in and assert
control? The professionals of the SS.
So a Germany run by coldly pragmatic technocrats, that doesn't give a squat about controlling the East,
what moves would they make?
All of the fantasies about arming the Wehrmacht and fighting with them against the Soviets, are pointless
fantasies as the Wehrmacht was just as guilt of atrocities in the East as the SS and the police. It was a
war of racial extermination in which the Wehrmacht was fully complicit. So do you think Allied troops would
really want to side with those people?