Unable to change the resolution of my built-in display

I can't change my built-in display's resolution under Settings -> Displays. I used to see a drop-down menu that allowed me to lower the resolution but it's gone since I reinstalled Ubuntu 22.04.

However, I am able to change the resolution to 1920-1200 by running:

xrandr -s 1920x1200

The problem is that I usually connect my laptop to an external monitor and the above code does not work when that happens.

I would like to either:

1. figure out how to get back the dropdown menu with the alternative display resolutions

2. learn how to modify xrandr -s 1920x1200 so that it works when the laptop is connected to an external monitor.

I have installed nvidia-520.

xrandr output

xrandr -q

Screen 0: minimum 8 x 8, current 2560 x 1600, maximum 32767 x 32767
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-4 connected primary 2560x1600+0+0 (normal left inverted right x axis y axis) 345mm x 215mm
   2560x1600     60.01*+ 165.02  
  1920x1200_60.00 (0x28d) 193.250MHz -HSync +VSync
        h: width  1920 start 2056 end 2256 total 2592 skew    0 clock  74.56KHz
        v: height 1200 start 1203 end 1209 total 1245           clock  59.88Hz

xrandr output when connected to an external monitor

xandr -q

 Screen 0: minimum 8 x 8, current 4480 x 1600, maximum 32767 x 32767
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 509mm x 286mm
   1920x1080     60.00*+
   1680x1050     59.95  
   1600x1200     60.00  
   1440x900      59.89  
   1400x1050     59.98  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1152x864      75.00  
   1024x768      75.03    70.07    60.00  
   800x600       75.00    72.19    60.32    56.25  
   640x480       75.00    72.81    59.94  
DP-4 connected 2560x1600+1920+0 (normal left inverted right x axis y axis) 16mm x 10mm
   2560x1600     60.01 + 165.02* 
  1920x1200_60.00 (0x28d) 193.250MHz -HSync +VSync
        h: width  1920 start 2056 end 2256 total 2592 skew    0 clock  74.56KHz
        v: height 1200 start 1203 end 1209 total 1245           clock  59.88Hz

I had the same problem, and in my case, it's drivers problem.

Step to fix:

1. Open software and updates > additional drivers
2. changed driver to noveau and restarted (If the problem is fixed, stay with it), or then
3. Changed the driver back to the latest nvidia and it prompted a few windows to setup an "enroll MOK" during boot to allow those specific 3rd party drivers to work. Just followed the steps, rebooted
4. During boot it prompted a few windows where I just followed the steps, typed the password I created on the previous step and that was it. It is working normally now.