I used to have everything backed up to a 2TB USB drive. Which I accidentally dropped down the stairs. I lost thousands of family photos and documents. That changed my backup perspective.
I now have a Synology NAS, with 12TB in a RAID5 array (for a bit of disk redundancy). All my home devices, Proxmox servers etc back up here. The NAS also holds a few TB of media. Attached to it I have a USB hard drive (also 12TB). The NAS gets fully backed up to the USB drive nightly.
I also have a remote Raspberry Pi with a smaller USB drive (4TB) attached to it at my brother’s house (in another country), where I backup most of the contents of my home NAS. I don’t back up the media, just the important stuff. I might have to upgrade to a larger drive…