Meetings, project management, actual project work, recordings for Cover-related work, merch-related shit, sponsorship-related shit, promotional shit, stream-related things, etc.
It is not so much one thing, but a lot of things adding up. You have to remember, management isn't "management" in the traditional sense. They are more helpers that can assist the talents, but ultimately most decisions come down to the talents themselves. For example, for one merch set, they have to decide what they want for merch, find people to design the merch themselves, and get the okay for the merch. It is even crazier on the JP side, obviously.
You have to remember, a lot of projects are generally happening that cannot be talked about pretty much until they get released. Music production alone is a massive undertaking.