This guide will help you fixing the unable to locate configuration file thingy for launching the game.
How to Fix (Step-by-Step)
Right click on the game and browse local files.
Go to the launcher folder and run the launcher-installer-windows.msi
Click next and change the install path to the folder where you found the launcher-installer-windows.msi. It should look like this:
- S:GamesSteamsteamappscommonCrusader Kings IIIlauncher
It should work after installation.