Is it possible to mod the Homecities of the campaign?

I was able to modify the Homecity master file for one of the campaign civs, but the changes didn’t load in when starting the campaign anew, they only worked when I used the civ in a custom scenario.

I did delete the old homecity files that the game generated for my playthrough before testing, so it should’ve been loading from the master file, but nope, still the default deck.