Tenet's main thrust is that the future of humanity is trying to destroy itself through the past and "present" through inverting entropy. He tells that story using the concept of "inversion" -backward moving people, objects and sounds. Invert Tenet and we get "our" present: humanity is destroying its own future.

Interstellar's story can be interpreted as "love conquers all" and Cooper himself claims that's how the events of the story played out with the love for his daughter (and the rest of the people on Earth) transcends everything, namely gravity. The "explanation" for how Cooper is able to warp spacetime in the Tesseract is that it's a construct of "Bulk Beings" who exist outside of the concept of spacetime. Simply rendered, it's easiest to explain that people from the future with super advanced technology are the ones that saved Cooper and thus all of humanity. But think of how Amelia Brand conceptualizes time: a construct a being unbound through four dimensions can descend or ascend like three dimensional beings can similarly do in a valley or mountain respectively. Cooper says the Bulk Beings are us and again, the simple rationale is that they are from the future. But if they are truly unbound by time then it's just as valid to say that people from the "past" or the "present" are the ones responsible for the wormhole, saving TARS in the black hole as he gathered the quantum data and then placing Cooper in the tesseract where he can transmit the data in Morse to Murph.

Finally, in Inception, one meta-reading (and not mine) of Inception is that Dom's organization of a team with specific roles to carry out the foiling of one rich megacorp for another is that this is actually a parable for filmmaking. We see it with the roles of the characters in Dom's team: Eames -a dream 'forger'- is an actor: his job is to convince you what you are watching is a totally different persona that is not his own. Ariadne is a dream architect -a screenwriter. Arthur and Dom's actions as point people in shared dreaming operations can be understood as directors or creative producers though Dom's plotline complicates such reading since he explicitly avoids seeing the 'mazes' Ariadne cooks up which would imply he's a film director that doesn't use a script and I'm pretty sure that doesn't fly particularly well. Saito represents the commercial side of movie making who insists on being in close contact with the production team to see that everything goes to plan.

In the movie, the team comes together to impart to carry out Saito's goal of breaking up Fisher's conglomerate to prevent domination of an entire market. In a coded reading, this story is of one movie studio / producer puts genius directors, screenwriters and actors together to come up with a better "movie" than a competitor studio in order to protect his share of the audience. Dom convinces Fisher to break up the conglomerate through an elaborate dream within a dream within a dream wherein he goes so far as to convince Fisher that he's part of the dreaming process which results in Fisher being "Inceptioned"- his subconscious has been tricked into thinking breaking up the conglomerate is his own idea in order to be not like his father. Dom, as a film director, convinces an audience they are taking part in the filmmaking process.

Taking all three meta narratives together, Nolan's narrative is that we need to save the environment (Interstellar) to save our future selves (Tenet) and he's been using movies to convince audiences to pursue this goal subconsciously because we'll do something if we believe it's our own personal idea (Inception).