MEIOU and Taxes is a mod for EU4 that improves the game by a lot in various aspects including but not least the economy with the addition of populations and trade.

https://old.reddit.com/r/MEIOUandTaxes/

So the plan is to add population with different religions, urbanity and social classes based on provinces producing goods as well as having needs and trading with each other provinces. (for contextual reasons as well as performance limited geographical trade except for rare/luxurious trade).
Those populations should be the premise of tax extraction as well as military source based on their wealth and cultural recruitement practices.

I briefly implemented the static basis of this system for CK2 some months before CK3 came out so the plan is to take back the premises of that.

Sounds so good! Can't wait!

hmmm so how will you approach the modding for this ie for example go full out sinews of war?