Make a case for it; why it would be interesting to the community at large, why it would be an improvement over this shitheap of a thread, and have the work pre-done to populate it with several Prospering Threads that are either of prominent vtubers of interest to the community of this site or are informative of the vtuber industry and drama surrounding it. The threads should also cumulatively have a certain threshold of activity, they shouldn't be dead threads with only one or two posters. Think of some live service video games that have temporary alternative game modes; you need to have enough people to fulfill queue times reasonably, new modes shouldn't ruin the existing main mode people join for & the new modes have to float on their own longterm as well.
Vtubers are not in Nulls sphere of interests so you'd have to have some easy lift & shift threads to fill a subforum that are also interesting and accessible to read for him or anyone else without a pre-existing interest so they can get sucked in.
It's not impossible but 2 or 3 people are going to have to put the work in writing-wise. I would say it would be slightly easier than writing an application for a local government grant.