I have already read a bunch of threads and haven't gotten anywhere. I installed Ubuntu command-line only, then installed the Gnome desktop environment separately.
Upon booting the desktop, the proper resolution appeared. I went to Software & Updates >> Additional drivers, then switched to the recommended "Using NVIDIA driver metapackage from nividia-driver-430 (proprietary, tested)". I hit Apply Changes, then rebooted the machine once finished.
The resolution broke. I tried reverting to the original "Using X.Org X Server - Nouveau display driver from xserver-xorg-video-nouveau (open source)". No dice. The resolution remained at 1024x768.
After reading through the xorg.0.conf log it appears the monitor is not recognized, which is causing the problem.
$ xrandr: Failed to get size of gamma for output default Screen 0: minimum 1024 x 768, current 1024 x 768, maximum 1024 x 768 default connected primary 1024x768+)+) 0mm x 0mm 1024x768 76.00*
There is no x11/xorg.conf.d file. Output of X -configure
X -configure _XSERVTransSocketUNIXCreateListener: ...SocketCreateListener() failed _XSERVTransMakeAllCOTSServerListeners: server already running (EE) Fatal server error: (EE) Cannot establish any listening sockets - Make sure an X server isn't already running(EE) (EE) Please consult the The X.Org Foundation support at http://wiki.x.org for help. (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information. (EE) (EE) Server terminated with error (1). Closing log file.