Thanks for the reply.

This makes sense, but is there any reason MRS would see such a drastically smaller number compared to, what I assume to be, matrix.org instance numbers? My understanding based on the documentation provided is that MRS seeks federation-enabled, published rooms to index, and is the initiator of the connect. It doesn't expect other servers to reach out to it.

Or would this difference essentially be from servers that decided to disable indexing BUT still federate with matrix.org?