[customkitchen]

Most of your comment is pretty bad misinformation. X11 was not designed to use Xrender. That was an optional extension that came later. And on many drivers, the drawing of XRender is still not actually GPU accelerated either. Remember that XRender was designed long before GPU drivers were in the state they are now, back in the era when people still thought 2D acceleration was going to be a thing. And, XRender is extremely limited to a small handful of primitives that were mainly used to implement the postscript drawing model used by cairo.

It is also not trivial to reduce the amount of roundtrips in an X11 program. If the program uses Xlib then it probably needs to have significant portions of it rewritten to use xcb, which is a lot more complicated than it seems because Xlib handles a lot of caching and logic that xcb simply does not. In some situations X11 roundtrips are simply unavoidable. Complaining about GTK or Qt will not change this. Even if it were possible to fix those, there are less and less contributors to those projects who are willing to spend time to maintain X11 support.