To be honest,
I feel the reason why many give this movie a high rating is because of the "Emperor's new clothes" effect. You would feel stupid for not saying this is a good movie, because you were not smart enough to understand the intricacies.
I would say this is far from being Nolan's best. The plot is convoluted, and there are too many gaps in the movies. He conveniently ignores many difficult and illogical concepts with plot armours. If you don't accept the premise of the movie, you will never be able to move on. Inception was a great movie because at the end of it, you know what you don't know, and you can slowly piece the movies when you think through it.
In tenet, you still don't know what you don't know by the end of the movie. I felt like I sat throughout a whirlwind of action and sound, without really knowing where it was leading to.
In sum, I felt that Tenet was a case of trying to be smart of the sake of being smart. But it grossly fell short of Nolan's other great movies.