To begin...
Incipiam is a simple bash script that uses launchctl and system_profiler to open and close programs depending on whether my USB-C monitor is connected.
I would like to thank reddit user /u/quantam_libet for the advice and code snippets to get me started.
If you'd like to adapt this script to fit your needs, fork this repo and use the launchd_template.plist file to get started.
Once you have a script you'd like to execute, put the modified launchd_template.plist file in $HOME/Library/LaunchAgents and load the new job with $HOME/Library/LaunchAgents/launchd_template.plist
After that, macOS will execute your script at intervals, even after restarts.