Right you are, it does appear to do what I am looking for. In the taskbar icon > monitor configuration. Its split screen does function for programs like notepad when you maximize it only occupies half the screen, above in this case an overlay of a fully functional taskbar. Maybe I am still missing functionality here, but in that same menu it offers an identify monitor button, that posts a big 1 on my entire monitor, and in its mini display of my screen it shows my monitor split by a white line, but i dont seem to know how to get it to identify the splits as two separate monitors identifying the upper as 1 and lower as 2, or in the case of the wallpaper menu 1.1 and 1.2 and this is evidenced by full screen games which when opened in full screen mode ignore all of this, occupying the entire monitor.
I only bought Displayfusion...mmm...about 10 years ago and only to create one screen on 2/3 monitors, when there was no native way to do that in windows. Not until the GPU's started implementing that. Then I bought a GPU that allowed that.Just fiddle around with it and search youtube for other users that want to do something like you want.
What you want is just not possible at this point in time. Maybe some where in the depth of the world some one is writing a program like that. Doubt it however.You would have been better off getting two small monitors stacked on top of each other.