I don’t think geoblocking would be a great fit for Matrix, since you’d be contacted by servers from all over the world. It’s more suitable for something like a static website

There are various technical alternatives (ActivityPub-based stuff like PixelFed/Loops/Mastodon/GotoSocial/Sharkey/Akkoma/something else on the Fediverse)

But would you take the plunge of self-discovering different content, which might as well be none of your topics of interests? Would you be acquainted of vastly different UI/UX such as the lack of recommendations, a million client frontends, and the technicality of federation? And lastly, will you find it a place with communities to socialize and content to enjoy from in the long run?

I think trying out on a public instance would be a good way to answer those questions. PixelFed most closely resembles Insta, but the other ones can do too. Then you can consider selfhosting your own

How on earth do you have 54 release candidates, each of them adding significant feature, and not bumping your versions? Wouldn’t it be nicer to just put them on the main branch and cut a semver release every now and then? At least that’ll save on the frequency of posts here

When you say “on each device” you mean this configuration would refer to the services running on that device right? Not that every client device needs to have this set up?

The device that runs multiple services will set that up, yes. Not the client.

All my web services use apache or lighttd. Do I use caddy just for this or do I have to figure out how to move each of them to use this web server?

Apache and lighttpd can both do the same thing that Caddy does (multiplex many services via subdomain names on port 80). Caddy is just simpler and hence recommended.

You can move all services to use Caddy, takes some learning but overall better. Alternatively, if you already set up apache/lighttpd for each of your services, you can put Caddy in front and do something like

http://service1.devicename.lan/ {
    tls off
    reverse_proxy localhost:<port-that-apache-listens-on>
}

Also does it work for non-web services, like ssh or samba? (Which wasn’t in my original question, I only thought of it now.)

No. Also, those should be running on their dedicated ports anyways

Use Caddy on each device, with tls turned off. Basically

http://service1.devicename.lan/ {
    tls off
    reverse_proxy localhost:8000
}
http://service2.devicename.lan/ {
    tls off
    reverse_proxy localhost:8096
}