For me the configuration that you build clearly generates a sddm.conf.
with having services.displayManager.sddm.wayland.enable
set to false
╰─ ls -alh result/etc/sddm.conf
lrwxrwxrwx 2 root root 53 1. Jan 1970 result/etc/sddm.conf -> /nix/store/17zdhjjczgs2xfirz8lzv5pmkwpbl21a-sddm.conf
╰─ cat result/etc/sddm.conf
[General]
DefaultSession=plasma.desktop
DisplayServer=x11
GreeterEnvironment=LANG=C.UTF-8 QT_WAYLAND_SHELL_INTEGRATION=layer-shell
HaltCommand=/run/current-system/systemd/bin/systemctl poweroff
InputMethod=
Numlock=none
RebootCommand=/run/current-system/systemd/bin/systemctl reboot
[Theme]
Current=breeze
CursorSize=24
CursorTheme=breeze_cursors
FacesDir=/run/current-system/sw/share/sddm/faces
ThemeDir=/run/current-system/sw/share/sddm/themes
[Users]
HideShells=/run/current-system/sw/bin/nologin
HideUsers=nixbld1,nixbld10,nixbld11,nixbld12,nixbld13,nixbld14,nixbld15,nixbld16,nixbld17,nixbld18,nixbld19,nixbld2,nixbld20,nixbld21,nixbld22,nixbld23,nixbld24,nixbld25,nixbld26,nixbld27,nixbld28,nixbld29,nixbld3,nixbld30,nixbld31,nixbld32,nixbld4,nixbld5,nixbld6,nixbld7,nixbld8,nixbld9
MaximumUid=30000
[Wayland]
CompositorCommand=
EnableHiDPI=true
SessionDir=/nix/store/fsxrh4ambgsc11arnb7s3fjp9w0kj49y-desktops/share/wayland-sessions
[X11]
DisplayCommand=/nix/store/p5lav04ppa1844r2jn1534qm0fs582d2-Xsetup
DisplayStopCommand=/nix/store/ib5ak7pyc3daypvvq1sycq83awz516x2-Xstop
EnableHiDPI=true
MinimumVT=7
ServerPath=/nix/store/ydybhrzdbwjlws3bb82sna1vr3868r0k-xserver-wrapper
SessionCommand=/nix/store/ar36n7wr14050isypp6440gnpf7lkpwr-xsession-wrapper
SessionDir=/nix/store/fsxrh4ambgsc11arnb7s3fjp9w0kj49y-desktops/share/xsessions
XauthPath=/nix/store/lxwa7w70v4460x4smpsyzw098l87vn7i-xauth-1.1.3/bin/xauth
XephyrPath=/nix/store/0c9wn8nb04qs9kyh2zhll4wzjmp0fmag-xorg-server-21.1.13/bin/Xephyr
with having it true
╭─ ~/dev/test ✔ took 22s at 21:37:20
╰─ ls -alh result/etc/sddm.conf
lrwxrwxrwx 2 root root 53 1. Jan 1970 result/etc/sddm.conf -> /nix/store/wrw8qp3fmmi3848j9jqqc687bw9k7qzw-sddm.conf
╭─ ~/dev/test ✔ at 21:37:30
╰─ cat result/etc/sddm.conf
[General]
DefaultSession=plasma.desktop
DisplayServer=wayland
GreeterEnvironment=LANG=C.UTF-8 QT_WAYLAND_SHELL_INTEGRATION=layer-shell
HaltCommand=/run/current-system/systemd/bin/systemctl poweroff
InputMethod=
Numlock=none
RebootCommand=/run/current-system/systemd/bin/systemctl reboot
[Theme]
Current=breeze
CursorSize=24
CursorTheme=breeze_cursors
FacesDir=/run/current-system/sw/share/sddm/faces
ThemeDir=/run/current-system/sw/share/sddm/themes
[Users]
HideShells=/run/current-system/sw/bin/nologin
HideUsers=nixbld1,nixbld10,nixbld11,nixbld12,nixbld13,nixbld14,nixbld15,nixbld16,nixbld17,nixbld18,nixbld19,nixbld2,nixbld20,nixbld21,nixbld22,nixbld23,nixbld24,nixbld25,nixbld26,nixbld27,nixbld28,nixbld29,nixbld3,nixbld30,nixbld31,nixbld32,nixbld4,nixbld5,nixbld6,nixbld7,nixbld8,nixbld9
MaximumUid=30000
[Wayland]
CompositorCommand=/nix/store/rizf7g8a5w26lxamz1f5d41knd01pivk-kwin-6.0.4.1/bin/kwin_wayland --no-global-shortcuts --no-kactivities --no-lockscreen --locale1
EnableHiDPI=true
SessionDir=/nix/store/fsxrh4ambgsc11arnb7s3fjp9w0kj49y-desktops/share/wayland-sessions
[X11]
DisplayCommand=/nix/store/p5lav04ppa1844r2jn1534qm0fs582d2-Xsetup
DisplayStopCommand=/nix/store/ib5ak7pyc3daypvvq1sycq83awz516x2-Xstop
EnableHiDPI=true
MinimumVT=7
ServerPath=/nix/store/ydybhrzdbwjlws3bb82sna1vr3868r0k-xserver-wrapper
SessionCommand=/nix/store/ar36n7wr14050isypp6440gnpf7lkpwr-xsession-wrapper
SessionDir=/nix/store/fsxrh4ambgsc11arnb7s3fjp9w0kj49y-desktops/share/xsessions
XauthPath=/nix/store/lxwa7w70v4460x4smpsyzw098l87vn7i-xauth-1.1.3/bin/xauth
XephyrPath=/nix/store/0c9wn8nb04qs9kyh2zhll4wzjmp0fmag-xorg-server-21.1.13/bin/Xephyr
The X11 content is there, because you have still set services.xserver.enable = true
.
That would be empty if you set it to false, tho that could likely be removed, ill check that out.
But i dont see any problems on the config that you have provided with generating a sddm.conf, so either you have other configs set that you did not include in your example (the steam-apps.nix and hardware-configuration.nix are missing), or some strange setup that hides the /etc
, for understanding that it might be helpful to have those files also.
Or if that in overall wasnt the question i possibly just missunderstood you, which is also possibly
But as it seems to be more a sddm topic, it might be better to open a separat thread then.