You are correct, that logging into TV using the local LAN IP address doesn’t leave the PC site, so it can never intersect with a “commercial PC site”. This always works, even after you get locked out with using your (web) PC address registered at TV.
Also, an entire list of hidden passwords can be made permanent for a device, by going into Extras/Options/Security and defining permanent Password(s) – or delete them there as well. Thank goodness that TV didn’t make that more complex than their commercial sniffer.
TeamViewer is pretty good for local IP connection, but after they started their campaign to unload all their free non-commercial users with their recent tactics, I decided to start moving myself onto TightVNC, which seems almost as good as TeamViewer so far, and even has a decent “file transfer”. Still need more practice with T-VNC though.