My instructions work for those running Plex in a docker container. To make things easier I have deployed my patched version to the Docker Hub registry:
https://hub.docker.com/r/mauimauer/plex
so instead of the official plex container or the linuxserver.io variant you could run mauimauer/plex.
However I have attached a patch in my first post allowing those who want to do so to have insight into the changes I’ve made.