Sharing for money with strangers.

Plex likely has been monitoring offerings of “Plex Shares” online, identifying a pattern of where they are hosted primarily, and taking action.

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I would recommend you look into Saltbox, which seems to align with what you are looking to do and should take considerable heavy lifting off your plate.

The solution to the rclone issues you discuss is to use a union mount, and cloudplow or similar to automatically shift files to the long term storage location, while Jellyfin will continue to see content files spread around servers in one mount location.