If the vanilla experience in Hearts of Iron 4 isn't doing it for you, a total conversion mod might do the trick. These are ...

So you looked at the long list of Paradox game converters, able to convert one single historical timeline of save games all the way through Attila: Total War, Crusader Kings 2, Europa Universalis IV, ...

"Should I take those three fertilizer missions, or rather the 2.3 ha potato harvesting contract?" "How much liquid fertilizer will I need for this job?" If you ever asked yourself questions like these ...