I would think they'd essentially play it by ear. Japan is doing relatively well vis-a-vis COVID. Right now it only has about 5,000 known active cases. If that number continues to drop substantially UF might feel confident to venture into concerts again.
I'm sure that this has been financially devastating to UF but personally I love the level of access that we have been getting with all of these little home videos. Perhaps they should offer a convenient method for users to financially contribute, whether through the youtube "join" button or some other method convenient to domestic and international fans alike.