That seems to be one of the common places where The Big Mistake by Der Fuhrer seems likely. There were others - like the Battle of Britain, which was only won by a whisker. A few extra days of heavy pressure in the early autumn of 1940 could potentially have led to a British wipe-out. Crafting an invasion after that would have been a different level of problem, but with air support gone it wouldn't have been totally implausible.

There's a recent book about Canaris which suggests that he was more active in a kind of high-level internal resistance than was previously suspected. The ideas are still controversial, but the suggestion is that he fed Hitler false information at various points to influence decision making, having realised that after 1941 there was nothing more to play for.

I like counterfactual history a lot. Although with a date of 2148 I'd guess the reality is more likely to involve people poking pointy sticks at each other, or some form of ultra-technology that hasn't been invented yet. (And since the last few years seem to have taken place in Bizarro Universe already, possibly both.)