I think from the technical point of view, it should be possible for users to merge multiple communities into one. I think the git software could be a great template for achieving this. The admins of each community would only be responsible for their instance of the community. The same merging could apply to comments.

The big challenge however would be to automate this into a seemless experience for the user. If the goal is to attract more users, the user experience has to be on a tiktok level of simplicity.

An additional problem, where I don’t have an answer yet is: What is supposed to happen if two communities start in the same way, but develop into different directions?