I think Top Gun 2 will be huge, and yes I think it is set to be a more successful film than Tenet. But, that's just my opinion.
As for your claim that Tenet is a "british film", why would audiences think that? Dunkirk was a massive hit in the UK but that is part of our history. I don't see why audiences would associate Tenet as being British? It's not set in the UK and it's a sci-fi spy movie with an American cast. It's an American film. in fact disregard audiences, why do you even think it is a British film? it isn't.
As for IMAX - it's not impossible for both have IMAX screens.
I personally suspect Top Gun might move forward a week or two.