nixos-config/home/desktop/monitors.xml

<monitors version="2">
  <configuration>
    <layoutMode>logical</layoutMode>
    <logicalmonitor>
      <x>0</x>
      <y>0</y>
      <scale>1</scale>
      <primary>yes</primary>
      <monitor>
        <monitorspec>
          <connector>DP-1</connector>
          <vendor>GSM</vendor>
          <product>LG ULTRAGEAR</product>
          <serial>110MAZVPXP89</serial>
        </monitorspec>
        <mode>
          <width>2560</width>
          <height>1440</height>
          <rate>164.958</rate>
        </mode>
      </monitor>
    </logicalmonitor>
  </configuration>
</monitors>