@Turambar I'd be happy to provide guidance on what my script is doing to somebody with the Linux skills to adapt this. Unfortunately I don't have the resources (test environment and time) to develop the mod for another environment.

RIP Linux players :'(

Helpful bunch ya'll are

No worries! Nice that you got it sorted out. I'm glad to assist whenever I can.

@Erik Taurus, Thanks for jumping in to help. I should have followed up here to make it clear. I talked with Questinable in private messages to Questionable. And thanks bringing the flaw in my instructions to my attention. I'll update the mod description to properly reflect both changes that need to be made.

@Questionable: You have to change the path both in the launch.ps1 and the launcher.bat -files.

e.g.
launch.ps1
$Input="<your custom steam install folder>\steamapps\workshop\content\489630\2571507843\Data\World\Blueprints\WorldParameters.xml"

launcher.bat
start "Gladius" "<your custom steam install folder>\steamapps\common\Warhammer 40000 Gladius - Relics of War\Binaries\Windows-x86_64\Gladius.exe"

Is it supposed to just open the folder location or run the exe of gladius cause it does the former and not the latter--

Notepad or any other text editor should be able to edit the script.

How do I edit the powershell for if I have a custom game location

Nicely done! Very clever using a Powershell Script to add some randomness to the game