+1 for Unraid, as it’s what I use, but truenas I believe has array options which support your plans no problem. It’ll do a similar software raid solution which allows you to modify the drive pool later on.

Thanks for the share.

I’ve actually just ordered one for myself as they officially support third party operating systems. I intend to be setting up unraid on it.

Leaving this here because it’s free and potentially solves your issue.

Snapdrop.net

It works similarly to airdrop and the only requirement is that the site is open on both devices on the same network.