[TOMT] [MOVIE] Sci fi post apocalyptic animated movie I saw as a child, similar to Nausicaa of the valley of the wind

Theres a film im sure i watched at a very young age, im guessing around 2008 to 2010 or even 2011, on a local argentinian kids channel (PakaPaka), I barely remember it and ive been doing research for ages now yet found nothing.

So its a sci fi/post apocalyptic animated movie: the color scheme was mostly dark and warm tones; i have a hazy memory of a character on a hill facing the scenery which was an orange field, i believe there were some sort of bases (?) and labs around, and the sky was almost totally black. The plot is pretty much unknown to me, but similar to Nausicaä and the valley of wind. I used to think that was infact the movie since ive watched it many times on that same channel but i rewatched it recently and im sure its not. The similarities i find are the sci fi theme, surviving in a contaminated world and ofc the spores. It was smt along the lines of spores falling like snow which is higly toxic, so humanity had to pretty much hide and try to find a solution or a way to live in that new enviroment (kind of like The eternaut) I also remember there were labs and sicentists working through the movie as to fulfill that objetive. Despite the comparison, its not anime as i remember the style being western, likely to be and old film (prob 90s or earlier?)

Id say there also were creatures that came along w the spores snow, and the characters sometimes had to fight them, but not entirely sure.

Ive checked many posts w similar descriptions in this community yet none quite fit my concept of the movie. Also checked movies under those categories (scifi/post apocalyptic/fungal even) but nothing. Was abt to give up as i kind of feel it doesnt really exist or im mixing stuff up, but im giving this one last chance