Neat. I wish OpenSSH better support this use case. The instruction involve multiple moving parts on top of OpenSSH (s6-ipcserver, socat or custom scripts) and a number of extra options for the client. That probably adds overhead. It would probably be easier and more efficient if OpenSSH would directly support Unix sockets.
Thanks for the explanation. I’m considering Matrix but will hold off, at least until v1.11 or v1.12 solves the unintended CDN issue described in another comment here, cf https://matrix.org/blog/2024/06/20/matrix-v1.11-release/#continue-reading