I hope it can be turned off.
I don't like PC, but it's passing time, and I installed it for the event on the forum. Then I began to see how autosave worked.
I was growing blue tulips, and waited hours for it, and I hit harvest instead of Xpollinate. And it freaking autosaved.
I can't play New Horizons that way. I know myself and my limits.
I'd end up hurling the console into a wall, so I really hope it's not a 'set in stone' feature.
BOTW's autosave can't be turned off as far as i know (or recall) but you can always revert back to an older manual save if you messed up, it is how i expect it to work in NH.
Yeah, mobile games mess up due to auto saving all the time