Backup software recommendation?

Does anyone have any recommendations for good backup software? My use case is pretty simple. I have an external usb drive I want to backup to every so often. Both the source and backup drives are 8TB capacity (I’m not even close to using the full capacity yet)

Normally the backup drive is left unplugged but I want to be able to plug it in run the backup software to copy across anything new then unplug it again for storage.

Simple file backup (not looking to do a full bootable OS drive backup or anything)

Thank you