There’s not a way to change it on an individual level.
As far as I’m aware / heard, when an instance has it disabled, it doesn’t even store information (or process) downvotes, so even if you could override it (such as by using a third party client) there’d be nothing to view.
I could be wrong though, might be worth trying some of the mobile apps to see if it displays it, just to confirm. For desktop, there’s also Photon.