I'm unsure what you're asking for? You could replace Netbird with any other WireGuard implementation and Caddy with any other reverse proxy. I just found those two to be very self hosting and FOSS friendly options.
As for what to use it for it allows me to run Jellyfin from home, while having Authentik be a forward authentication proxy in front of it so only people with an account can reach it while still allowing me to reach it from any device anywhere with Internet. It's very nifty.