@ThatJungleGaren Things to consider:

Many factions start with heroes and you can get heroes from different events, you can also get more heroes when making confederations or when a faction is eliminated with the mod Recruit Defeated Legendary Lords https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id = 1736529254
If you want to be able to recruit you can use mods like Less Agents / Heroes [July update] https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1149645211 with higher priority.
Agents do a little what they want, I can't do much more.
All the mods that I have tried that prevented the agents from assassinating also prevented the creation of underground cities and similar actions, so I consider that in this aspect it is unique.
In advanced games (turn 60-100) the agents can carry out some offensive action but it will be very isolated.

Hey, this looks great, but wasn't sure about something. When you say agents cant be recruited, does this apply to the player as well? I like having heroes in my armies, but hate getting them assassinated by AI, would this mod fix that?