Make objects in portals collidable in 2D

Hi, I followed this tutorial on how to make a minimap

, and used the same principals to create these kind of mirror portal objects. So when one portal sees the ground or a platform, it will appear in the other platform through the rendered texture. Im wondering how to make the newly appeared platform a collidable object in the other portal. Here is a picture for reference, https://imgur.com/a/QJa5x0b.

So the purple circle is a platform that already exists and has a collider, and the red circle is what is appearing in the portal but currently does not have a collider because it is just being rendered on a rawimage. Currently if I jump onto the red circle area my character will just follow the gravity mechanics and fall right through. im curious how someone would go about adding colliders to it.

The way the boxes work is they are both cameras that output to a render texture and the render texture appears on the other camera's box.