What a great idea. Corrupt both versions at the same time!
I think you’re missing the point there. If the external drive has the media on it fr Plex, then depending on your needs / risk appetite then running a RAID config may be a good idea. For example I run a RAID0 pair of HDDs for the media drive enclosure to give it some performance boost. Yes I know this increases the risk of failure, but then I have two separate backups of it. By “both versions” I assume you’re referring to RAID 1 mirroring or some other configuration. RAID provides operational resilience for a volume of a hardware failure and/or performance gains, it is not a backup strategy.