Hi
I run home assistant on my pi3
Can I install plex server on same pi3 and work together?
You might want to explain a little further what it is you actually want to do? You certainly can install both. But if you want transcoding from plex a rpi3 might not be powerful enough to do that.
~Cheers
Yes you can, however Plex can be quite hard on a Pi3, and you may run into problems with delays to your automations, or intermittent problems. You’re better off running Plex on a different Pi3.