I am trying to understand Wayland protocol but can't grasp that a window manager tells display server where each windows are. So is display server a renderer or compositor?
I've been searching for the answer myself for quite some time now as well.
I will try to provide a partial answer.
Reading the official docs it seems to me that, using the wayland protocol, the display server, window manager, and the compositor become one single program.
For example, xorg is a display server, i3 is a window manager, picom is a compositor but sway is all three.