So i've narrowed my problem down to needing to have infinite money and infinite soil turned on. Why wouldn't i only need infinite soil?

I have the exact same problem. Didnt try the infinite money solution.

same problem. I got the limit on one map and then, exited, reloaded the game, loaded another map. It's like I'm limited in the 2nd map as well.

Im having this problem too, any solution?

I had this problem to. Solution:

Have the infinite money mod on.

Imagine there is 10 units of land. To terraform 1 unit it costs 1$. Now imagine that this mod makes something like a 2nd currency. When you terraform the land with the mod on, your money does not decrease, but at the same time it does. Since it has created a 2nd currency which only changes when things are terraformed it will take away those $ from the 2nd currency, not the normal one. And if you get normal money, lets say another 10$, you will get another 10$ in the second currency, but yet again when terraformed the original currency does not change, the second one does.

Same here, activating infinite money seems to have fixed the issue. Unfortunately the author has retired from modding CS so it looks like that's gonna be the only way to properly use this mod unless you have tons of money in your bank.
Edit: looking through old discussions i found that the author enabled the mod to use money for terraforming bc it was a requested feature back in 2016. I guess a game update probably broke the way he implemented this.