It does work in the other direction. A qcow2 file created with virt-manager is able to be run with a qemu command.
That supports what we have concluded, qemu simply ignores the metadata and set up its own.
I have found that the display window you get with qemu + spice has some limitations, compared to the display you get with virt-manager. It would seem that virt-manager does not use any of the qemu display options, but instead sets up its own inbuilt display function.
Thanks for the backup and restore examples. I need to learn about virsh… have not used that.