Sorry if i'm asking something dumb, but i searched in some threads and the TP discord and couldn't understand if the use of Nintendont is just restricted to category extensions or valid for the main leaderboard.

Nintendont is considered an emulator, which is only valid for the extensions leaderboard. There are a few main leaderboard categories on there for emulator submissions as well.

Thank you! again sorry if the question was dumb :P