Is there a way to orthographic a specific mesh from the perspective camera with a shader?

Hi, I am not too good with shaders but another way to do it would be: You could use two cameras, one perspective and as a culling mask only those layers you want to be rendered in perspective view and the other one orthographic with a culling mask for only the layers you want to be drawn in orthographic view. You can then use the orthographic camera as a overlay camera for the main camera (perspective camera). But you'd need the URP (at least version 7.2.1) for that, else you can't stack cameras on top of each other.

Here's a little package with a scene in which I did the thing I explained above. Package

Hope it helps!