Just two either 16GB or 20GB HDDs to work as backups of each other. The USB hubs for the HDDs would need to be powered.

I was looking into getting raspberry pi to make a home server for data storage and jellyfin but it’s similar price to a notebook. I’ll see if there will be some cheap notebooks since windows 10 is ending, the only problem would be how to connect HDDs to it since through USB it would be slow I assume.