It gets even more automated/complex when you add in something like overseerr which pairs up with sonarr and radarr to read your library and allows your users to search for a title and request it if it’s not in your library. With the click of an approve button the automation will have their desired title on plex in a matter of minutes.
Everyones process is a little different but that sounds unnecessarily complicated. See my other comment about the arrs through docker. You could probably do it all in a single compose file.