Maybe you are not sensitive to it. Some people dont percieve tearing as much as others. I run base PopOS (ubintu derivative with gnome) and i get tearing in x. I don’t know much about linux jist that when i login i can choose x/wayland and wayland seems to be a lot better at everything (fractional scaling also works).

I can consistently trigger it playing a video in any player under X11 e.g. videos in Firefox or in a standalone player like mpv/VLC etc. It's pretty damn obvious in certain types of videos e.g. action movies. But always on Intel GPU so it's possible it's not so noticeable with other GPU due to hardware or driver software differences. The Intel driver for xorg has a configuration flag that stops screen tearing.

IIRC I get it in Firefox occasionally. I vaguely suspect some combination of smooth scrolling, video, and a portrait mode screen but it isn’t annoying enough to investigate

mpv running an anime for example, where the scene pans to the left or right

Sometimes adding a compositor like Compton helps, but you still see it