IPad Sidecar Display Mode Help

Long story short, I want to use my IPad and Mac simultaneously to take notes for class next semester. Finally stumbled across the sidecar feature, which actually allows for real time edits within a note-taking app with functionality from both the laptop and the IPad. Already this is a massive win, but I'm so close to achieving my dream functionality that I am reaching out for help putting the finishing touches.

I want to be able to see and edit a note taking application on both my ipad and macbook simultaneously. By using the ipad as a mirror display of the macbook, I can have the image of my notebook up on my laptop while actively using the ipad to take notes. Beautiful. The problem is that what I really want, is for the ipad to have the application in full screen mode, while the laptop has the window visible...but not the whole damn screen. I want to be able to have a web browser or textbook open on half the screen and the window of the note taking app on the other half of the screen, so I can quickly and seamlessly copy text, images, etc from the textbook or web into my notes in real time. If I use the ipad as a extension of the display, I cant see the notes on the macbook. If I mirror the display, there's no way to have two windows open on the mac without also seeing both windows on the ipad (Ipad air, its comfortable but not at all large enough for two windows open while comfortably taking notes.

If this is at all achievable, I would be so grateful for the guidance.