Yes, that’s really the only plist file you need for macOS Sonoma and higher.
The installation flow is basically this:
- on a test machine, install your screensaver (using the iScreensaver-built installer app). Do a “for all Users” installation as indicated.
- get the plist, and a copy of the .saver bundle that was installed
- roll out the .saver bundle and the plist on the target machines.
It’s a long thread, so perhaps you missed it, but these step-by-step instructions begin here: Understanding the macOS Sonoma screensaver plist - #5 by iScreensaver