I got distracted from my work so I made some Continuwuity propaganda. Continuwuity is a lightweights Matrix chat server that you can self-host pretty easily. Give it a try :3
You don’t need to share any server technology names, just that it’s the Matrix protocol or “platform”, or even just “Element” if they are using that app. I don’t tell other matrix users they are on a Synapse server.
Only the host needs to know about the server app name, and is the only one who interacts with it directly.