This looks so absurdly fun, shame bout being only oculus
Right now, only Oculus Quest / Quest 2 have actual camera-based hand/finger tracking without controllers, letting you use your actual hands to their full flexibility. You can even recenter the space so that a real wall is where the painting is, to have the full tactile fingerpainting experience.
Unfortunately, with controllers in your hands, it would be a stiff crummy experience, as they are just poor approximations of where your fingers would be.
I hope someday the other headsets will come out with controller-less hand/finger tracking too! If Oculus Quest, which is cheaper than all the desktop headsets, can do camera-based hand tracking with a mobile processor, then why can't we have controllerless hand tracking capabilities for expensive desktop headsets, right?