I have an older system76/galago laptop(Intel graphics). I use it with 2 external 4k(HP/Z27) monitors with no issues. Previously used with 1 4k, 1 1920xSomething/Portrait. Resolution switching works fine. Also, PopOS gnome UI comes with build-in tiling, feels like slightly nerfed i3. It also works fine across monitors/virtual desktops and so on. PopOS desktop is X11 based and I havent played with Wayland on that laptop