Honestly, I didn't understand much when I watched it for the first time in theatre. It was too complex & loud and the dialogs were not clear. But when I studied the timeline and watched again, it was mind blowing 🤯. I even watched some sequences in reverse playback to get it better. Respect to Nolan to even think something like this in head and tried to execute it.
Tenet is clearly a new approach on time travel. It may seem boring & messy unless you put some effort to deep dive into it. I thoroughly enjoyed it in my second time watch.