I would either get a used HP Proliant microserver Gen 8 (I own one. Pretty sweet) or get a mini ITX nas case, 4 or more bays. Depending on USB doesn’t seem like a good idea to me. You can always sell your mini PC. I have slowly learned to avoid the sunk cost fallacy.

How is bazzite as a daily driver?

The reliability could be hit and miss no? These could have a bajillion hours on them, depending on where they came from. 20 may be a bargain, until you have to keep replacing them every 2 years or less. Just guessing here.