In this example we install debian 10 with --variant=minbase which gives us a minimal/tiny install. Don't use variant if you want the full size install.
mkdir /tmp/deb10files
debootstrap --variant=minbase buster /tmp/deb10files/
Did you get an error?
debootstrap --variant=minbase buster /home/theuser/VMs/deb10files/
You'll get this error if you make a directory in your home........