For my buddy and I our critical data doesn’t change often so once or twice a year when we get together we swap drives again. Simple spinning discs for us. No need for hardware or anything to keep them running. They just sit on a shelf just in case something happens we can hand it back to pull the data back onto a running server

My friend who lives a thousand miles away swaps hard drives with me that are backups of critical stuff. He keeps my data, I keep his. As others have said your garage is a start but you really want some sort of geographically separate backup.

That econdary drive I highly recommend you find a way to move that out of your house. For me I have a friend 8 hours away, we swap drives on occasion to keep each other’s backups in case of flood/fire/toddler or whatever other force of nature to save ourselves cloud backup costs