Redundant backups onto separate drives and computers (servers) is the best solution I have found. Backups can fail
Having a backup.backup in an "air-gapped" location can save the day.
You can buy a USB3 to SATA cable and hook up a SATA 6 drive. You can buy an OEM 1TB SATA6 for $50 - $60 today. Buy 2 and you will have redundant backups. I format as FAT32 or LINUX ext4 -- never trust NTFS
Data is worth money so is time and aggravation -- operating systems can always be reinstalled or replaced.