Search function prioritizes matrix.org rooms, increasing centralization of [matrix]

### Your use case

This is especially bad for matrix.org accts.

Anyone can spin up an instance true. But the matrix search bar for most users (many are matrix.org) mainly indexs matrix.org rooms meaning non matrix.org rooms are very difficult to find. To find non matrix.org rooms, services like lemmy have to be used and they have to be active promoted there.

### Have you considered any alternatives?

Using 3rd party websites to find rooms.

### Additional context

_No response_

The issue names no files, tests, or entry points. Begin by tracing the Matrix room search and indexing behavior described in the report, then define and verify a ranking change that makes non-matrix.org rooms easier to discover without relying on third-party sites.

Written by the indexing model from the issue text.