I did it! Thank you @MainAkkount
I got a tip for the people who aren’t finding the lines:
There are more than 1 line with the same name, but they already have a 0
So, to be more specific, you can check if it’s the correct line using the bottom bar of your Notepad
It will start on Ln 970, Col 39, and you need to put zeros until Ln 978, Col 44
Then you open the game and all progress will be reset
So if you want to restore the progress of your Blood, Ice and Steel you can set the values of 4, 8, 8 in the lines 970, 971 and 972 (gamecampaignselected, gamecampaignprogress, gamecampaignfarthest)