Question Camera / Canvas advice

Hi, I hope I can get some information from your experience on this one

We are building a 2D App (UI only) – maybe some very minor 3D rendering on top of the UI later on.
We are also using URP.

The way we set it up now is an empty Main scene with a script and a camera.
From here we load additive overlays / masks / screens (as scenes)
We are not yet sure if every scene should have their own camera, and how this would effect the performance.

The canvases are set up as Screen Space Camera for the most part. We would need to find our camera and apply it to each new loaded scene then.
As far as I know we need to have this setting to use URP features and lighting / glow etc.

Easier would be to encapsulate each scene with their own camera, what is best to do in this case, any "non guessing" advice / experience is highly appreciated

I'm coming from 3D, so sorry that I'm asking this kind of maybe easy/ obvious stuff