Or remove the battery if you can, to spare it from pillowing. I know it has the benefits of being a “psuedo-UPS”, but unless you also have your modem/router on a UPS, it’s pointless (internet goes out; you can’t access the laptop anyway).

The feature is called DDNS (Dynamic DNS).

It’s not exactly difficult if you use Tailscale or really any VPN. So I really don’t see the value for the cost; if you’re even considering self hosting a Plex server/instance, there’s a list of basic knowledge you should have or learn (like what you mentioned).

If you can run tailscale or similar, your IP becomes a non-issue (CGNAT vs static IP)