I might be in the minority here but I, for once, loved the first one. I didn't find it tedious or boring or anything like that, really. It resonated with me, well enough that I beat it twice (the original on PS4 and the Director's Cut on PS5). Just saying this cause I might not be the right person to ask for opinion on the second game, given how differently we feel about the first.
But to try and answer your question as unbiased as I can be:
There's more action.
There are more (and different kinds of) bosses.
There are more (and different kinds of) BTs and human enemies.
There are more weapons.
There's more stuff in general.
The core game remains the same: you are a porter. You bring stuff from point A to point B. Sometimes from point A to point B to point A again.
The gameplay feels like a mix of Death Stranding and Metal Gear solid V in a weird (but good) way.
And that's it, I don't know what else I could tell you. Hope this helped in some way!