I agree with @browned. Recently, I was extremely close to moving my server to an alternate Linux based OS that supports drive pooling/merging and parity natively. The only reason I ultimately decided against it (and sticking with a Windows OS with Covercube products) was completely unrelated to my current storage needs.
I would buy a new product or extension to my existing Drivepool license to have this functionality!
IMO, at the enthusiast level, without lots of money for extra drives or homelab level hardware, being a datahoarder gets truly complicated as you fill up the machines