The more-or-less unarguable fact that Hitler's invasion plan for Britain was deeply flawed needs to be considered in the context of the level of authority Hitler had and the way he made decisions. The first thing is that nobody had the authority to override Hitler and very few were willing to even question his decisions. So the opinons of the senior military lesders within Nazi germany were only relevent to their own careers, and not to the decisions of the Fuhrer.
The second thing is that Hitler had repeatedly succeeded with moves that were successful because they were so unexpected - common sense and orthodoxy ruled out trying to move his army through the ardennes so when he did it he took the entire world by surprise. Over time it would become apparent that Hitler was far from a genious, but in 1940 this had not become obvious.
As a result Hitler had developed an undeserved reputation as a strategic genius, which meant that invasion paranoia was an entirely rational response, especially when you have aerial photos showing the preperations for an invasion.
Had Hitler given the order to invade history would have changed - if Britain had succumbed he would have been free to turn his hand to Russia until the completion of both the Manhatten project and ultra long range the B36 bomber by 1947 created existential problems for his regime.
The the other possible - and far more likely outcome - would have been a failure of the invasion, which would have in turn raised questions about the wisdom on taking on Russia that even his own generals might have been unable to ignore