I reworked the entire map and I got this


I tried with no shadow this time, just to see if it's better or worse (or anything else).

I tried to make some kind of Pantanal (Brazilian wetland) in the middle: Pantanal - Wikipedia, the free encyclopedia, and a representation of Brasilian Caatinga in the east: Caatinga - Wikipedia, the free encyclopedia

Can someone tell me some advice to improve my technique and style?

Thank you in advance.