Even though I've liked Nolan's films overall his films since Interstellar have had a curious trajectory. Before I comment about that I want to make a comment about how one of the shortcomings of film-by-film criticism is that people who take one movie at a time tend to lose sight of a director's catalog or a screenwriters' cumulative arc. So with that in mind I want to highlight a theme in Nolan's films running from Memento up through The Dark Knight, the self-deceiving protagonist. A director so consistently drawn to protagonists whose motivations are based on deliberate or unrecognized moments of self-deception across two decades was going to have a hard time selling us a simple and uncomplicatedly ethical protagonist even if he's played by John David Washington (who I hope has a long and hugely successful career).
In Memento a man kills his own wife (on purpose or accident can be left for debate), gets an injury that costs him the ability to form new short-term memories, and he then goes on a quest to avenge the murder of his wife without realizing that he is himself the one who killed her, leading him to commit what he regards as a righteous act of revenge that continues his legacy of killing.
Take Nolan's remake of Insomnia, where Pacino's character is an investigator in a battle against a killer (Robin Williams) who knows that Pacino's character got convictions in murder cases by doctoring evidence. Or The Prestige, in which the protagonist goes to obsessive lengths to solve the magic trick set up by twins and along the way reveals to us, the viewers, that he's the real monster and not his perceived adversary.
Thus, by the time we get to The Dark Knight trilogy (which I wrote about in "A Path Through Three Prisons") we're seeing men (Ducard and Bruce Wayne) who embrace violent paths of retribution against what they regard as the crimes rampant in society without observing their own roles within those cycles of violence at best or, at worst, rationalizing that "this time" what they're doing will end cycles of corruption. Because Nolan could not just posit Bruce Wayne as a completely self-deluded grief and fury-driven lunatic we get a heroic arc but the central moment in the trilogy has Bruce Wayne choosing to take responsibility for Dent's crimes so "the Joker cannot win", because "sometimes the truth isn't good enough. Sometimes people deserve more, to have their faith rewarded."
People who have not tracked Nolan's filmography from its start to present might confuse Nolan's crime trilogy with being thematically central to his overall work. It's actually the aberration both in terms of having a traditionally heroic protagonist and in terms of the protagonist's arc. If we go back to Nolan's films and move forward this becomes easier to see. The core motif that runs across Nolan's filmography is about men and self-deception, what rationales they have for deceiving themselves and why they believe that believing in, or at any rate, fighting in the service of a known lie can be ennobling, if only, perhaps, to the man who believes it. Batman reaches a moment where he realizes that he can't live by or with the lie he told to posthumously protect Dent from his crimes and their consequences for rule of law.
Then we get to Inception where Cobb has to admit he's responsible for he's wife's death if he's going to escape a dream-world of his own design. So Nolan can have characters, men, who reach moments of epiphany where they realize they should not live by lies and make other people live by them.
But then you get Interstellar and Dunkirk. The plot twist in the first is that "we" humans in the future figured out how to save ourselves and communicating via block hole convey information to humanity to find a place to live. That was a pretty absurd ending and a signal that Nolan's ability to convincingly sell heroism rather than self-deluding quasi-tragic protagonists is on the weak side.
Dunkirk ran with the idea that society can't continue without us collectively lying to ourselves about our nobility. It's in blink and you miss them moments such as newspaper articles talking about a boy's death in relationship to heroic rescue operations whereas what we saw in the film was a shell-shocked British soldier killed the kid in paranoid and thoughtless anger. Nolan has trouble with Steve Rogers Captain America style heroism because he reflexively draws back to a notion of societies in general being founded on lies and how do people give their lives and fight to the death for those?
Which is why Tenet comes off as so completely unconvincing. If Sator is a broker who deals with "the future" and gets weapons from anonymous antagonists in the future how did they contact him? There are hints that people within the Protagonist's own organization reached out to Sator but on the whole Tenet is a film where Nolan has tried to give us the most positive protagonist in his filmography and it devolves to James Cameron style time paradoxes and Michael Bay set pieces.