I use and love the plex home managed users feature for all the devices in my house. It makes it super easy for people to turn on a tv, select their account, and start watching the shows they have favorited or where last watching. Really, this is a key feature that makes it possible for me to replace streaming services.
The problem with managed users is that they are local to the server only. Everyone in the house has their own plex account but logging into their account is too much work on the TVs (hence why we use plex home managed users). However, their watch list and progress is not synced between the managed user and their personal plex account.
What we are missing here is either an easier way to allow people with full plex accounts to use the TVs in the home without having to jump through login hoops OR we need to be able to linked a managed user to a full plex account and have everything sync between the two.