As far as I'm aware Plex media server still has the option to whitelist subnets for auth bypass. I don't know if there is an option to do purely local authentic

As far as I'm aware Plex media server still has the option to whitelist subnets for auth bypass. I don't know if there is an option to do purely local authentication, but I don't believe it's accurate that the company is holding the keys to your library.