OPs request was could they do it with pis. Yes you could. HDD is max 120mbs, with SSD over USB interface you get a lot more even thought its not running on the pcie bus. It is totally functional as long as you aren’t streaming 4k to your TV. And it is more than enough for most people. As a reliable backup solution it works, but best if you use a drive enclosure that is powered, rather than relying on the USB power of the drive adapter.

You seem irrationally irked about a viable suggestion, to OPs orignal question. Sorry if I triggered your inner nerd 😀