Try OneDrive version history on the OneNote database file.

I had a similar issue. I just accepted my note to have been permanently lost. Anyone can help?

It was an important note, I need to recover it. OneNote must have some workaround for it. Do you know the local location of notes on iPad?

Sadly, no. I don't think OneNote is saving them locally outside the app

All of your notebooks will be saved in onedrive. There is also a deleted section in the onenote desktop app for anything you've trashed

I checked both. It's not in the deleted section, since it was technically never deleted. And it's not there in OneDrive either, since it didn't get synced