I wonder, will HA work fine, if it runs on the same server as Plex and it making some transcoding. Do you have such installation, any thoughts?
It probably would work fine. But at least for me the operation of Home Assistant has to be stable and smooth, so I wouldn’t risk its snappyness by running it on a machine that’s doing some heavy lifting from time to time.
I am running Home Assistant and Plex on the same server, with a i5-6600T CPU (2.70GHz, 4 cores), 16GB RAM and a Samsung 950 Pro 256GB, and I’ve never had any issues with Plex transcoding impacting on the responsiveness of HA.