OMG. This has been a feature that has been asked for at least 6 years ago. It can be simply addressed by adding the geoip module to nginx in the Plex distro.
Nginx supports this...
https://docs.nginx.com/nginx/admin-guide/security-controls/controlling-access-by-geoip/
But the libraries are not included in the NGNIX app that is included with Plesk. Can that be rolled out?