Yes, external displays can break in weird ways. I remember that a common annoyance used to be that windows and applications don't go back to where you left them before suspending. There are likely other paper cuts as well in areas of variable refresh rates, colour management, etc. I think the biggest issue with external displays, screen tearing, is solved now due to wayland. As for hw and distros, stick to intel or amd igpus, especially in laptops. Both gnome and kde are pretty good these days. Ubuntu and Fedora are both quite good. Distros aren't that different anymore these days. The differences boil down to release cadence mostly.