Someone posted this on Reddit. The plex integration in hass doesn’t work for cloud systems and from what I understand is not realtime. This is the golden ticket. Worked first try for me with a cloud plex server and it was real-time!
EDIT: Okay, implemented this with some automations for changing lights when a movie has an action of pause/resume and there is a delay of about 3-4 seconds.
Edit2: there is now a webhook implementation that I believe is faster.
Thanks a lot for the share and looks like a great solution considering the official Plex component for HA is dead since ages (developer has nearly no time to fix it if I understood well 
Going to try that today in my system 
Wow impressive as it’s really real-time (compared to broken plugin included in HA that took 3/4s to update each time !). Thanks a lot for sharing that very good tip 
Thanks
Side note. I think the webhook solution is even faster than this.