I don't know if I'd give up hope on more content for New Pokémon Snap just yet. The DLC was only just released in August, which was like three months after the game came out, so it's possible we might get another DLC drop around Christmas they just haven't advertised yet. The latest Animal Crossing game is still getting new content over a year and a half after its release so it's entirely possible we'll see new stuff for NPS in the future.

That said, I do need to finish playing it. I love the game a lot but I can only play it in small doses because it makes me motion sick, haha.