Nazi wunderwaffen were often the idea of a single individual and they certainly depended on funding from a single individual with a decidedly short purse. In fact the most decisive factor in a lot of German ideas 1933-1945 was if Hitler turned up for the demonstration. The R&D was haphazardly funded and vital ingredients were often in short supply because of Germany's terrible strategic and resource situation. When attention from higher ups was directed to the project it would usually be to make insane demands , demand impossible production numbers or completely redirect the projects goal.
OTOH allied R&D went through committees but they were generally sound and they were funded to the hilt. Nutty ideas like Habbakkuk got to the point of a first tech trial and were dropped. Manhattan did not get the go ahead because one dude was sold an elevator pitch, it went ahead because they asked everyone including Einstein who had a clue and they mostly said it would fly.
Manhattan was 2 billion well spent, I think it represented an amount equal to 10% of German GDP at the time. This is why the notion of the Nazi bomb is so ludicrous, even if we grant them some efficiencies (not demonstrated IRL) to compensate for materiel shortages as well as agreeing that with less than half the elite scientists available to the WAllies they still have to cut everything else by 10%. Given the Eastern Front was hanging by a thread for the better part of 3 years I'd say that puts the Soviets in Berlin as the first bomb rolls off the line. Maybe they get to burn a Soviet front in atomic suicide but its not a war winner.
Most WAllied funnies were simple practical measures (like rams on tanks to cut through the bocage and landing craft), or else high dollar value solutions to logistical problems (like PLUTO and Mulberries). Soviet solutions were much simpler and cheaper, and typically relied on mass. The Nazis have airborne brigades (OK I know they had 13 Fallschirmjager divisions on paper but they never dropped more than a brigade or two at a time)? Build an Airborne Corps. Nazis have some nice medium tanks? Outproduce them 2:1, and make the tanks simple and soldier proof. Nazi airforce is effective? Compensate for inferior engineering with overpowered engines and winterisation.