Maybe there's a better metaphor but with lend-lease it's like, okay so if you loan a forklift to the workers who have to do the heavy lifting, you'll then try to take all the credit when they're done with the heavy lifting?
Tbh there's a bit of a case for the Brits since they held off the Nazis in western Europe until America joined the war, then acted as a base of operations for coordinating the D Day landings and they were also important in the North Africa campaign. But tbh Britain mythologises this way too much and I'm really sick of seeing the whole cottage industry this country produces of films about how we won the war