Finally watched Tenet. After all the hype and discussion on Reddit when it was released, I was expecting some sort of neigh-on impenetrable profound piece of cinema, but it's just Primer with action sequences.
I don't really understand why people act like I'm bullshitting when I say it wasn't confusing. Don't get me wrong, it wasn't linear, but I understood the basic concept.
There are parts that go "forwards" in time and there are parts that go "backwards" in time and the streams of events influence each other when they meet. The relative perception of the characters is that all events go "forwards". Some characters pass through the macguffin machine and their flow starts going backwards, and they influence themselves in both directions. Past this, you just have to watch the story happen.
The only confusing thing about the movie is the visuals. We're not exactly used to watching shit happen backwards so shit looks weird sometimes. The big fight with a ton of soldiers was probably the worst at that.