I assumed they already were.

No chance Plex wasn’t making money from those who didn’t pay for Plex Pass.

I use Windows and have never encountered what you are describing.

none of my files have ever been ‘moved’ to OneDrive and none of my files that are on OneDrive have ever been locked behind a paywall.

the easiest way to get them to care is if someone is actively invading theirs.

I make an upload to the toilet a couple times a day.