Yeah, my son convinced me to try having one monitor vertical. His (Windows 10) is close to right, but dragging a window across the gap and you have 2 different size windows. Compared to my computer (LMDE) and it is truly scaled correctly, the window is the same size on any monitor and while travelling between them.

Still not sure how I feel about a vertical monitor though, it’s great for documentation but just feels so unnatural.