Not sure what you have against minimum wage, it works well in other countries (I’m from the Netherlands). Obviously it doesn’t solve everything by itself, but it’s definitely a valuable part of a range of measures to treat people fairly. It’s a fantasy that everyone can be educated to a level above minimum wage.
Object storage (the S3 API stuff) is the most logical answer here, it’s much simpler and thus more reliable than solutions like Gluster, and the abstraction actually matches your use case. Otherwise something like an NFS share from a central fileserver works too.
But I agree with the other comment that you’re trying to do kubernetes on hard mode and most likely with a worse result.