Dunno. I just feel like the end got a bit mumbo jumbo-ey.
I personally think the whole thing is a bit like that, honestly, setting the tone from the get-go with the weird dodge where it's obviously a future ruined by climate change but Nolan is too afraid of his own fans or perhaps just "controversy" (I think that's the reason) to call it that, so it's "a fungus" (and what would cause such a fungus to spread, hmmm?). I don't know exactly how to put it - it's like he's not willing to commit fully in the way he did with some of his movies (even some not-great ones like Tenet I feel like he "committed to the bit" more), or that people like Kubrick did.
He's a
really good visual film-maker who basically had three good ideas ever AFAICT, all relating to the human mind and personal identity (Memento, The Prestige and Inception), and everything else that hasn't been about the human mind and/or personal identity has been, imho, beautiful, striking, memorable, and kind of ultimately hollow (very much including his Batmans, albeit the middle one is pretty great despite that). That said I haven't seen Dunkirk or Oppenheimer (yes honestly I'm surprised I haven't either!) but have heard good things about both from people I respect so I presume he can do historical too!
(EDIT - The Prestige may be in my top 10 movies period, and what an improvement from the merely ok book! He changes the fundamental concept from a wishy-washy one in the book to a
much more disturbing one and it's brilliant.)
I'm very excited to see his take on The Odyssey because I give it 80% chance to be a deeply unintentionally hilarious disaster (Matt Damon as Odysseus! It's like an SNL bit from 2005!), and 20% chance to be a masterpiece (I pay that it doesn't fall between these two stools and become merely "boring", but I'm not sure he's ever made a boring movie - albeit The Dark Knight Rises and Tenet came close at times, but never quite got there, not on a first viewing anyway).
But maybe I’m missing some details or nuance.
You definitely are not missing anything. I've seen the film a few times due to other people wanting to watch it (I personally enjoy it less every time, except the fight scene, which just becomes funnier, and the visuals, which I can focus on more). There's nothing really there. It's just wishful-thinking space magic that doesn't even have the emotional impact of say, Star Trek IV, let alone the wildness of 2001, which it clearly wishes it was.