Maybe someone else understands your question, but I don't
Are you asking about changing the laptop screen resolution?
or connecting a second monitor at a different size and/or resolution?
or running the OBS app at one resolution and other apps, on same screen at a different resolution?
All of the above a controlled by physical hardware and the operating system, not OBS. And 2 resolutions on 1 monitor is not something I've seen in consumer space (if it exists at all)
As you aren't changing the laptop screen's physical dimensions (height/width) nor its maximum resolution [true for all monitors], your option is to
- display lower resolutions, as monitor supports
- set up a virtual display that is larger than physical screen
Or are you asking something else?