This is a terrible solution, a secondary camera is expensive. We need a checkbox to disable culling and / or perhaps a custom bounding box we can set up. This is insane.

For now I'll try to move the canvas position in the player's face before rendering, and call an event in a custom pass when I'm drawing the custom pass to move it back to the original position for correct matrices.

A solution for certain cases is to have the UIs on a different layer, only visible to a separate camera and disable occlusion on it.