ENTRY POINT IS launcher.ps1
I wanted a tool to use for this purpose, and I made it. I put it here for anyone else who may need/want it :3
Without modifying the functionality (launcher.ps1), or building/compiling anything, you can just edit the window.xaml, apps.json, and icons in the icons folder to customize the launcher for whatever you need.
To change general coloring, you can go into window.xaml, and change Background="" and Foreground="" attributes.
The only exception to that is the Setter: <Setter TargetName="border" Property="Background" Value="#e81123" />, which is self explanatory on how to handle and alter it.
Preferably use .ico files, since I only implemented support for them, and I don't know if any other file format will work.