Hitler ended up, from his view, fighting the wrong war.
He never thought, (with good reason) in the 1930s that his advances in Europe would eventually lead to war with Britain.
France was another matter, as a WW1 vet he probably considered attacking France as unfinished business, after all, Nazi ideology made much of a mythical 'undefeated' German army being stabbed in the back by Communists and Jews in 1918.
And the French army in 1939 was the largest in Europe, the French state had at some time to be taken out.
But with the UK, Hitler thought he had a natural ally, he admired the Empire.
Some gullible people on sanitized Nazi approved 'tours' of the new Germany gave this impression credence to him.
Hitler had originally planned attacking Russia much later, but the declaration of war by Britain and France in 1939 upset things, he probably would have favored a knockout blow to Russia, when he was absolutely ready (German war production was not in full swing until around 1942), then deal with France.
By the mid/late 1940s, German naval power after the 'Z Plan' programme would have allowed the offsetting of the Royal Navy. in case Britain did come to France's aid.
That's important, as if the UK did need to be invaded, he'd need air and naval power, in 1940 he tried to bomb the UK into surrender, Sealion as a plan was not taken seriously by the Wermacht, as they had no amphibious transport, just large numbers of modified civilian barges, even a Luftwaffe with air superiority sinking many RN
ships, probably would not have stopped the RN
decimating a German invasion force stuck on barely sea worthy barges.
A few RN
cruisers and Destroyers anywhere near fleets of barges packed with men and material, with only some German Destroyers and E-Boats to protect them, would have been a massacre, the Luftwaffe would have had to sink or disable every RN
warship in the Channel to really protect the invasion.
Just a few RN
ships surviving this could have been fatal for the invasion.
Now if he could have attacked the UK at his choosing much greater German Naval power could have tipped the balance.
If you are invading an Island, or just trying to fully subdue it, you need very substantial Naval power.
In 1940, having stumbled into war with both Britain and France the previous year, Hitler had a problem, how to make the British 'see sense' and sue for peace.
Goering said the Luftwaffe could do it, but the Sealion invasion was not a really thought through plan, had the Luftwaffe won the Battle of Britain most likely the main effect would have been to make resupply of Britain more difficult, as ports, railway lines, all the infrastructure in fact now easy targets for the Luftwaffe, the U-Boats would do the rest, the UK would eventually sue for peace as starvation loomed.
When it did not go that way, Hitler turned to his real target of Russia.
But in keeping some control of the Mediterranean, by kicking the Italians all across North Africa, the UK was far from passive and licking it's wounds, Hitler had to come to Italy's aid.
Resources that would be needed in Russia, were in Africa, no doubt Hitler thought that it was worthwhile as if the oil supplies could be seized, it could be a potential knockout blow to Britain.
After early German success, the defeat of Germany in North Africa by the Desert Rats was a turning point, though worse was to come at Stalingrad.
Nazi ideology always was about making large parts of European Russia a new German empire, by miscalculation, misunderstanding of his potential enemies, belief in his own supreme tactical prowess, Hitler made his own dreams impossible to realize.
He must have been concerned enough about the UK still being in the war, even at Britain's low ebb of 1941, by sending his deputy Rudolf Hess, on a crazy mission to Scotland to it seems, cut a peace deal.
When it failed, he just could not resist taking the risk of attacking Russia, as the Red Army was in disarray and Stalins terror ripped through Russia, Hitler must have thought that the hour had arrived.
He was big on his believed 'destiny' after all.