Ouch, that hurts. Backup and Restore (Windows 7) is still part of the Windows 10 OS and I did not suspect at all that it was deprecated 4 years ago. I feel like an idiot, I have spent many hours in those 4 years maintaining the backups.
There are two quite separate functions in Backup & Restore, the System Image which can restore a replica of your working system in the event of a drive failure, and a files backup. It is the system imaging that was deprecated.
Even when it works the system imaging is awkward to use with little or no user options. There is no easy way to restore individual files from a Microsoft system image, it's all or nothing. As long as it can recognise a system image the restore is reliable though. I used it for years before switching to Macrium Reflect Free.
The files backup is more reliable, but has the disadvantage that (being designed in the days of floppy disks) saves the files to a series of linked .zip files with a master catalogue. There is no way to manually extract files, you need a working PC with Backup & Restore installed.
What I obviously still need is file backup. I have File History, but having another file backup software may be a good idea. I don't like installing third party software on my workhorse, so ...
... is there file backup software that can be installed on a USB stick or on the external backup medium itself?
One of the many advantages of Macrium (and most other 3rd-party system imaging) is that a Macrium image can be mounted as a virtual drive. You can then explore it with File Explorer to retrieve any file(s) you may need to restore. As such, a system image made with Macrium Reflect Free can be all you need. If you want a selective files and folders backup, then that is in the paid-for version.
You can never have enough backups, so in addition to my Macrium images I have also written a batch file to backup my important folders using the Microsoft command line utility RoboCopy. I also have File History turned on.
If you want a ready made files and folders backup, then I have seen others recommend Karen's Replicator. I've not needed to try it myself as I have my own solution, but it does get recommended frequently.
Automatically backup files, directories, even entire drives! Karen's Replicator copies selected files from one drive/folder to another. Source and Destination folders can reside anywhere on your network.
www.karenware.com