A very nice way to fix a backup is to make a copy, bootable, of the actual SD card You are using on the Raspberry Pi(RPi). This will be done even when the RPi is up and running !
This application can also be used to make a bootable SSD or USB drive !!
You clone from the command line so You don't need the standard GUI, Pixel, and the "SD card copier" function.
It is also possible to set up a a scheduled job, cronjob explained later, which for example makes a clone every night at 1 o'clock.