It can be done right: local only connections (no cloud), segmented vlan for iot devices with strict firewall rules, Internet access blocked for anything that doesn’t need it, etc.

Unfortunately that takes a lot of knowledge and effort. The cloud based devices that phone home every few minutes are preconfigured and just work, so most people will just use that and not think about it.

Teamspeak has a pretty slick new version that looks very much like discord. Not fediverse but pretty easy to self-host.