If the US inspections of offshore oil rigs are any indication of our lack of ability to fix things obviously broken, I can't imagine nuclear power plants would be any different, except the risk in a nuclear scenario would be amplified.
Why couldn't you store this in your Plex account, versus on the storage medium?
Everything is routed through Plex's services, seems like you could decouple those two things quite easily while still having full encryption on the cloud storage.
In fact, if Plex really wanted this to succeed, they should have a tool which encrypts the files, synchronizes the files with the cloud provider, and then releases the keys to Plex.
Indeed, this does follow a global pattern.