Yeah, I was on Linux at the time, and I’m pretty sure the answer to how you’d go about flipping your display is “it depends how your graphical setup is set up. On KDE, you do XYZ in settings. In Gnome you do ABC in settings. In Cinnamon you do MNO in settings. If you’re using a more minimal WM on X11, you type xrandr *something something* in a terminal. If you’re using a Wayland compositor it depends which compositor. On Sway you’d do swaymsg *something something*.” Etc.
(Not that I couldn’t have done it for my specific setup without too much effort, but surely there’s a good portion of users out there who weren’t using phones or tablets and had setups where they didn’t know off the top of their heads how to rotate their screen in software.)