Oh, I'm actually aware of that :D But the growth! It's just impossible... Not only did I not manage to do it, but I was even late... And on top of that, you need to spend extra money (there are a lot of upgrades in the third game) on heroes (!), which in essence will only be a chain...

If it were impossible, I wouldn't be writing this :) It was tested in practice during offline games and on hot-seat. I'm not claiming that you'll gather every single unit, you just choose the most necessary ones. There were usually 8 heroes in the field, and in each castle, there was one hero in the inner courtyard. And when I talk about a chain, I don't just mean gathering troops one by one. You can also transfer ransom from a castle to the main hero via a chain. In the fourth game, this is basically impossible, and no caravan has the same mobility as a chain.