[1.15.2] Creating a "Second Camera"

Hello!

I am curious on how I would go about creating a "second camera" for use with perspectives. In the past I have heard methods of creating a client side entity and then using setRenderViewEntity() to switch perspectives. However, I want to take this a bit further and Create a second popup window (that can be dragged onto a secondary display) giving me two perspectives independent from each other. The concept would work similar to splitscreen or even those popular free cam mods.

My basic thought process for this is as follows:

Create client side "camera" entity, would act as if I were running the game with another account (in regards to a camera view)

create a second game window with the secondary view - when window is in focus you would be able to move camera around, but cannot interact with GUI's etc.

So how would I go about doing this? Would I need to create a frame buffer/render to texture and do some of that weird openGL related stuff?