Hammering it into submission is overkill, ugly, and not necessary.
Plex’s configuration on Linux can be customized per your liking.
I suggest looking at setting
a. PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR to store the metadata where you want it.
b. User= to change the username
c. Group= to change the group
You can set a configuration which uses the same username / group name used by other applications and services on your system.