Yes, but the word rewrite implies that it would serve the same function and retain compatibility.
If someone wrote a new implementation of the x protocol, as a drop in replacement for the existing x.org server, you might call that a rewrite.
Wayland is an entirely different solution to the same problem. It doesn’t follow the x protocol, and doesn’t maintain compatibility with the x.org server.
Endeavour’s current iso is still KDE 5 and X11, but if you do an online install it will default to 6 and Wayland. Just make sure to connect to the Internet before starting the installer.