I don’t have any input on your download direction… But I wanted to share some drive links.

Folks on datahoarder love these drives… Dell Exos X18 18TB SATA 6Gb/s 7200RPM 3.5-inch Enterprise HDD - ST18000NM002J (Renewed) https://a.co/d/9LeBkx7

And recertified drives / server pulls on https://serverpartdeals.com/collections/manufacturer-recertified-drives

Might be a cheaper couple of options for expansion.