i think the best thing that the germans could have used was the longer range v2 that they were developing
V2 is a perfect example of the muddled thinking that kept German production from reaching its potential. It did not come anywhere near the destructive power needed to justify the utterly massive expenditure of resources required by its development and deployment.
Technically impressive, yes. But strategically useless. Remember that the entire payload was about 1000kg....and that a
single B-24 was able to deliver two and a half TIMES that amount on a long range mission.
And the V-2 cost about $2 billion in development alone. Not to mention the costs of production, the production materials it consumed, the factory and labor production it required, and the literally thousands of lives (primarily of slave laborers) lost during those processes. Could those resources have changed history had they been spent on more mundane tanks, planes, and equipment? We'll never know.
Marvellous as it was, the V2 demonstrates more about Germany's "Cloud cuckoo land" production system than it does her technical wizardry.