Screen tearing in X11 is a tricky one since there's a dozen ways to deal with it and 10 times more ways for it to go wrong, which is just enough uncertainty that you can never be sure if it's supposed to be that way. I know I've spent hours trying to deal with screen tearing by fiddling with desktop compositors that are supposed to prevent tearing out of the box only to fall back to the trusty AMDGPU/Radeon TearFree setting which has always just worked for me.