It will still work if You slightly change Your setup.
- if You drives comes back as different device (like sda to sde) setup udev to name device by it uuid so drive should be reconnected and then remounted at same place
- setup something different than RAID - there are several ways for that - like mentioned mergefs
- pay extra attention for usb connector - what tkaiser mentioned: Quad SATA Hat Disconnects
- always You can do some disaster recovery - get some monitoring and do restarts
I would not keep there any important data, but still may be ok for second backup or some media player.