Sorry to sound argumentative folks but in the main going from some of the suggestions already made you're barking up the wrong tree.
Once it was known that the Allies were demanding unconditional surrender the fate of the war was sealed. Whilst they still had troops to field Germany would never surrender unconditionally.
Unconditional surrender meant being at the mercy of the Russians; this was in all respects unacceptable. One only has to remember what Germany went through during the 20s and early 30s as a result of communist agitation to know that they would never, never allow the Russians a free ride. It matters not a jot who was leading the Germans, indeed Donitz refused to surrender (and became hated in some areas of western Germany because of this), until he could hold the Russians no longer. Of course the war was lost but by 1944 the main mission (as viewed by those outside of Hitler's immediate circle) was not victory under arms but to save as many people as they could from the advancing Russians.
A failure to understand this most basic premise cost the lives of hundreds of thousands. Attitudes such as Ike's
"The only good German is a dead German" hardly helped and cause me to be reminded of a wartime cartoon.
A man is reading in a newspaper about the camps. Behind him are ghosts of the dead and dying from the camps. He remark's, "The whole German race should be hanged for this", a ghost comments, "Some of us are Germans, friend".
The issue of the early victory in France is a red herring. The 300,000+ troops saved at Dunkirk and those later evacuated from Normandy (some of whom had to fight their way out past French troops) were of no consequence in determining whether or not Britain could continue the war. Four years later these troops would be leading the liberation of Europe or would be in the Far East but in 1940 that was not the issue.
Short of developing atomic weapons Germany could never have defeated the UK. That is not the same as saying that the UK could in turn beat Germany far from it; although I do believe that left to their own devises it would have been Germany that would probably made the first move towards the negotiating table.
By 1941 the war in the Atlantic had been won - yes it took the various participants another two years to recognise that but nevertheless it was true in an objective sense. With supplies coming in the UK wouldn't starve. The German's never developed a bomber force effective enough to bring the UK to it's knees and any suggestion of invasion was simple stupid. As for Sealion, the German's called it,
"Reader's Haven Bound Command", the German's were simply faced with an impossible task. The UK being where it was geographically was in a position to interdict Germany at will and yet remain safe behind the waves. The obvious conclusion is that everything else being equal, as time went by Germany could only get weaker in comparison to the UK. This is with or without Russia, with or without the USA ... anything. Germany was and always has been at a massive strategic disadvantage for no other reason than it's geographical position and of course when it's fighting a maritime power such as the UK was the result was inevitable.
But no, there would be no surrender with Russians on the doorstep.
Sorry I tend to ramble on, I'll leave with a quote from Donitz (although he never meant to be heard). Sat behind his desk in his office the day Britain declared war on Germany an aid brought in the news. As the aid left, he turned to look at Donitz. Donitz cradled his head in his hands and was heard to say, every so softly,
"That this should happen to me again".
[edited to correct spelling and the more obvious grammar errors]