“IP” in this context means “internet protocol address”. A public IP is one that can be accessed from outside your home (what you see when you go to https://whatismyipaddress.com/). A non-public, or internal, IP is the one your router gives your computer, frequently starting with 192.168. This can be accessed by other computers on your network but not from outside your network.

This is for music not watched content, but Maloja and Multi Scrobbler are a pretty nice setup.

No recommendations for your actual post, but thought it might be useful for someone else.