Question about over colonization

I just got the game and have been enjoying it. I am around turn 50 on the tutorial game and I just realized I am over the colonization limit. I am confused about this mechanic because I can’t see a breakdown by hovering over it like the others. I am currently 9/7. I have the federation government which gives me extra slots for each leading hero of which I have 2, but I don’t know if that is already in affect and 5 is the base or not. I also just research CB Ed the imperial technology that is supposed to increase the limit (something anthropology) but it has not increased. If someone could fully explain this mechanic and how I can raise the limit I would greatly appreciate it. This feels like it is strangling my empires growth. Also, I know I can go into files and change it, I want to do a vanilla run through before I try that.