I wouldn't say its "plain impossible" with X11, but its significantly easier on Wayland because its a far simpler design that aligns better with the graphics hardware, we're sending surfaces (or pointers to them) with metadata to the compositor, not drawing APIs.

That already works with Plasma Wayland. It's still a bit finicky to make it work with things running in XWayland (Windows games primarily) but it's getting better.