How to acquire player position on render texture?

I have two cameras, one is an orthographic with the ability to rotate at 45 degrees around the player. I have it set large enough to project the entirety of my game space.

My other camera is focused on a render-texture. I want this camera to pan around the render-texture following the player.

I do not understand how to acquire the position of the player on the render texture.

I first thought I could position the render-texture quad above the game-space, then parent the camera to the player, however with rotation the camera goes in the opposite direction at times.

I have tried looking into WorldToScreenPoint, but I'm not quite sure how to implement it into my setup as the results are numbers that exceed the bounds of the render texture.