So I have this dashboard that can already display presence and battery information for HA: Cyberbeni/index.htmx: Lightweight server-side rendered dashboard. - Codeberg.org
(I also have this utility that helps with presence detection and cover control: Cyberbeni/Wiring: A set of utilities for Home Assistant. - Codeberg.org )
And then I have this forward_auth service that also does RBAC: Cyberbeni/auth.home.arpa: Minimal forward_auth service for Caddy and other reverse proxies. - Codeberg.org
Although for this use case I would add the functionality to the authentication service to return the username and the groups of the logged in user in a header that can just be copied over to the request so this “guest dashboard” would only have to be hosted in 1 instance with separate configuration per username/group.
Or people could also just have a single unauthenticated “guest dashboard” and then not bother with setting up forward_auth.
I don’t need this right now but if there is some interest, I might just make it when I’m bored. (It would be in a container, like all my other projects, I can’t help wrapping that container into an add-on, you have to figure that out yourself)
ps: Also comment what type of stuff you want to display / make controllable.