Backup recommendation W10 no admin rights

Hi backup experts, I am searching for an easy way to backup my wifes work pc, just some document folders, no image necessary, ~2gb total size. It's running Windows 10, she has no admin rights and other people might have physical access to it. If backup would run once a week it would be enough, but automated would be great.

Thought about 2 external drives/sticks which can be changed from time to time, but backup should be encrypted of course, since everybody can just grab the drive.

Is there any (portable) tool you could recommend for that use case? Or is task scheduler and script the way to go here? Any input appreciated :)