Undisort an image using Render Texture

Attached is a Unity project that shows my attempt at undistorting an image.

Camera 1 freely moves around the image.

Camera 2 copies the movement of Camera 1, but Camera 2 is looking at a Quad with the rendered texture from Camera 1.

The view from Camera 2 should show the marker as normal (no distortion or as close to no distortion at possible).

Is this the correct route to be going down?

Because Camera 1 is currently looking up at the marker, the marker appears squished on the Y axis on the Quad. I could therefore increase the Y scale of the Quad. But, I feel like I'm hacking my way to solution... !

There is no code in place yet, so I am manually moving the cameras.