Display manager does not start at boot when using autologin after adding amdgpu

I’m a new NixOS user. I have discovered that if services.displayManager.autoLogin.enable is set to true in the config the display manager does not run at startup anymore after adding amdgpu. It simply boots into a tty.

It does run if I sudo systemctl restart display-manager.service and I don’t notice any issues with my naked eye. I am not sure if initially it crashes or just doesn’t run at all.

GPU: 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Curacao PRO [Radeon R7 370 / R9 270/370 OEM] (rev 81))

Config to recreate:

{
  imports =
    [
      # See https://github.com/NixOS/nixos-hardware/tree/master?tab=readme-ov-file#using-channels
      <nixos-hardware/common/gpu/amd/southern-islands>
      ./hardware-configuration.nix
    ];
 
  # ...
  
  # Commenting these out fixed it.
  services.displayManager.autoLogin.enable = true;
  services.displayManager.autoLogin.user = "user";
}

I’m having the exact same issue - if autologin is enabled, wayland or plasma fail to start and I’m left staring at a text prompt. I’m on nvidia hardware, however, so this seems to be platform agnostic.