You are asking too many things.
Do you need a network access to shared folders? Then you need a dedicated NAS or a system running a NAS OS like unraid, OMV or truenas. Proprietary solutions are synology etc.
Apart from that you also want to run some software?
OP, there's no right answer tbh. It depends on what risk tolerance you have. Based on that you will have to decide on your ratio for debt:equity. As you near the goal you should be in very conservative i.e. fixed income or debt