With the enshittification of streaming platforms, a Kodi or Jellyfin server would be a great starting point. In my case, I have both, and the Kodi machine gets the files from the Jellyfin machine through NFS.
Or Home Assistant to help keep IOT devices that tend to be more IoS. Or a Nextcloud server to try to degoogle at least a little bit.
Maybe a personal Friendica instance for your LAN so your family can get their Facebook addiction without giving their data to Meta?
IoS - internet of shit