I'm trying to keep it civil, so I'll just say there are different interpretations of Britain's role in WW2.
You're not civil. If you were, you wouldn't even need to say it.
My view is that Britain and its Empire should not have entered the War at all. I think it was a disaster, and it's only a myth that we 'won'. Social/emotional pressure from people like you, who get your understanding of things from mainstream sources, props up the myth and deters/discourages people from examining things more closely and objectively.
When I was younger, I met/knew a number of former servicemen who had served in the War and who expressed similar views to mine above. Disdain for Churchill and scepticism about the War was quite common in Britain at the time it all happened, and the War was, for a period, very unpopular, especially among the ordinary working class.
In the first place, it was Britain (and France) that started the War, not Germany.
Hitler had no serious wish or intention to invade Britain, and his invasion of the western Continent (France, Benelux) was for strategic purposes. He would have happily given those countries their independence, under assurances that Germany would have a free hand in the East - which personally I would have had no problem with.
Ask yourself: Why, for example, didn't Britain and France ally with Germany against the Soviet Union, in order to deter the expansion of sovietism into Eastern Europe?
Was the fate of Eastern Europeans better under Stalin than under Hitler?
I could go on with the questions, but won't. The answers do depend on one's point-of-view and the type of person you are.
Britain historically has tended to ally with Russia in an effort to contain the two larger Continental powers, France and Germany. I think both of the 20th. century world wars can be viewed in that context, as Britain pursuing its geopolitical goals. Personally I am of the view that Britain should have stayed out of it and allowed Nazi Germany and the Soviet Union to fight it out, while developing its own defence - including an atomic capability - in order to face whoever won out or deal with the (more likely) 'cold war' stalemate at the end. Perhaps if it became clear that Germany would prevail in the East, Britain could have then joined on the German side to deal a death blow and then come to a strategic arrangement with Germany. There was a current of opinion within the British Establishment that favoured strategic alliance with Germany rather than Russia/the Soviets.
The Americans presented a complication. They entered the War officially/politically in 1942, but I would argue they really entered the War in the late summer/early autumn of 1940. That was the point at which they became
de facto belligerents, and Churchill's government in effect handed Britain's future over to the United States at that point.
The idea that the Americans did this to defeat fascism/Nazism, or whatever, is naive. Britain and the United States were still rivals in the 1930s, and had been at cold stand-off for much of the late 19th. and early 20th. century, and could have been at war. Some informed commentators earlier in the 20th. century had thought that the most likely 'world war' would be between the British Empire and the United States, with the main theatre being a war over Canada.
The Americans used destroyers-for-bases and Lend Lease to enter the War and finally take control of Britain. The situation was formalised in 1942, after intervention had become politically-acceptable in domestic American politics.
My central point is this: I favour British independence/sovereignty and the way to have preserved that would have been neutrality or strategic alliance with Nazi Germany.
The alternative, that Britain pursued, was a different Faustian pact, in which we handed-over our effective sovereignty to the Americans and bound ourselves into a liberalised international order, then under their encouragement, we ditched our Empire, allowed mass Third World immigration into the country, and sought to join the EEC (as it was then called). In effect, we became a puppet of the United States rather than a proud independent country.