Well it’s also that one of the main causes for WW1 and WW2 was Germany wanting to have what Britain had. I don’t mean the islands of the UK, I mean their globespanning empire of colonial domination. So necessarily, both world wars would orbit around the conflict of UK vs. Germany. Interimperialist fighting in both cases.

What was unique about WW2 was that there was a new wildcard, the USSR. The first proletarian non-imperialist superpower that created such fear and reaction in the bourgeois imperialists of Germany, UK and USA that the whole war went differently. Germany was allowed to metastasize by the other European powers in a hope it would collide with the USSR. Germany was overtaken by the blackest reaction and took on an anti-communist genocidal crusade, funded and backed by capitalists around the world to go Eastward.

The USA was dragged into WW2 on the side of the UK because of heavily shared capital interests between the two anglo nations. The USSR did whatever it needed to protect itself, stalling for as long as possible with ceasefires and then allying with whoever to repel the genocidal German invaders.