I haven’t used Plex in a while, but I presume it would go similarly to my Jellyfin migration this year.

I pulled out a 10 year old laptop from my pile of scrap, installed a light-weight Linux server that can run containers, and I’ve been running LinuxServer.io’s Jellyfin container on it. Updates are pretty easy and I don’t have to worry about cluttering the host box’s packages with dependencies that may or may not conflict with the other things I run in it.

If you have the time to figure out how to run apps in containers, I highly recommend doing so. There’s a lot of documentation for Docker, and Docker Compose files make managing the containers pretty easy.