So here's what to do:
Find the game ID in the game folder. There's usually an info file there.
For CyberPunk 2077 here's what to do:
Edit the game in Launchbox.
Application Path:
C:\Program Files (x86)\GOG Galaxy\GalaxyClient.exe
Application Command-Line Parameters:
/command=runGame /gameId=1423049311 /path="G:\Games\GoG\Cyberpunk 2077\bin\x64\Cyberpunk2077.exe"
Also make sure to put this in under Additional Apps:
C:\Program Files (x86)\GOG Galaxy\GalaxyClient.exe
And set it to automatically run before main application.
If I don't set this GOG Galaxy crashes for some reason.
Use your own paths to the software of course! Good luck!