I believe I got the answer: the last couple levels are gained only by completing at least some (if not all?) of the ambitions as well.
But those should be easy to gain with the mod. All you have to do is this:
- Start a new game in each ambition
- Select a monarch
- Select any quest
- Use the cheat "setqp 0"
- Quit the quest (and make sure your QP is indeed at 0)
- You'll get the congratulations screen and the ambition level should be at max
- SAVE YOUR GAME
- Quit to menu
I'm currently still testing this out, but it seems to be working so far.
And also, I realized I messed up the mod a bit. Some achievements weren't being completed properly. Here's the updated version: