Display managers are not necessarily tied to X11. Many of the supported display managers can be used with Wayland. However, the current options to enable/configure these are all behind services.xserver, and require services.xserver.enable = true; for any of the options to be used properly. This makes it quite difficult to run a pure-Wayland system without installing an entire X11 server along with a bunch of utilities.
Is there any reason we shouldn’t move these options outside of services.xserver? Does anyone know of anything that would break in doing so?