Since Plex is for home use, parental controls for time usage, preferably library specific, (so they could still listen to music but not watch movies) and also quiet hours, would help a lot. This would work much better for my home than straight wifi limitations.
The cited duplicate post in the other feature request no longer exists.
(https://forums.plex.tv/discussion/145310/feature-idea-limit-times-users-can-use-plex/p1#top)
I have searched extensively for this. It is no longer addressed in the plex feature requests.