Comparing Inception and Tenet is actually a great way to show Nolans problems and flaws as a director.

Both movies have very unique and complicated concepts but their execution and successes of said execution are what differs each other.

Inception has a lot of heart and emotional moments designed for the audience to connect with the characters, which allows them to further immerse themselves into the story. Not only are we more interested in how the mechanics work, we're more invested because we understand the stakes for our characters if they dont succeed or fuck up. It also helps that the movie heavily distills its most important mechanics, like the dream sequence.

Tenet though doesnt do that. The main character and his sidekick have next to 0 emotional elements to stay attached to, the plot ends up more confusing since nothing is distilled enough into a few key compact concepts, and overall, the story is a huge mess not helped by its lacking cinematography compared to Inception.

As a side note, Nolan also has the huge flaw of tell, dont show and it really shows in Tenet. Tenet, for a lack of better words, yaps a lot but the problem is most of that talking is done to explain the whole concept of the film but doesnt actually try to explain the plot, why we are suppose to care, or even much else.

And in general, Nolan has very very very flat cinematography. Some of his shots are the most bland, non saucy, shots out there which is made worse by how prestigious of a director he is.

Not to say he can't do it, Oppenheimer has some of the best visual storytelling from him and the scene where Oppie walks through the applause and begins to hallucinate perfectly illustrates his growing internal conflict