This will make any files/directories you create in the shared dir have the right permissions to share. But it doesn’t apply to files already existing in the directory or files/directories created outside of this directory that are moved into the directory.
If you go the VM route, you might look into QEMU + KVM using .qcow2 files for the VM disk. Then you could just copy the qcow around and start the VM with a command (albeit a complex command). If this sounds interestiing, let me know and I can provide help and examples of how I do it or explanations.