V-1s could be launched around the clock, they were dirt cheap, they were hard to shoot down before the investment of vast resources to defend London and the introduction of the proximity fuse shell and late model gunnery radar. London was the major rail hub of the country and an endless series of rockets falling on the city would put it under major strain. 1000 bomber raids didn't come frequently until 1944 against one of the worst police states in history and were effectively one off events vs. round the block bombing. There is a reason the Wallies put huge efforts into shutting it down IOTL (along with the V-3 gun).
https://en.wikipedia.org/wiki/V-1_flying_bomb#Assessment
I'm not convinced , Germany was heavily bombed even before 1944 and rockets are one shot weapons. In the best case scenario you shoot off a rocket, it lands somewhere and explodes and it contains all of one warhead. The rocket is now gone.
In the best case scenario a bomber takes off, drops a whole bunch of bombs, comes back and can do so again. V1s would do some damage, it wouldn't knock GB out of the war. It might or might not slow things down enough Germany instead of Japan gets nuked or it could wind up being such a waste of resources that Germany loses by '44. It doesn't win the war for them.