I am wondering is it possible to make DoW Dark Crusade or Soulstorm load an edited .lua file (that i previously extracted via Corsix studio & edited with notepad) - but without making it as a whole separate new mod that i have to switch to via the main menu?

I am very new to DoW modding and would like to just change one .lua called "destination_formation" for use in campaign and skirmishes.

Thanks for helping out!

I dont know for your file. I did edit campaign files for wargear points (for player and for AI) and region bonuses. Just extract them via some tools, put to proper Data folders and edit with WordPad.