Image showing a 3d terrain created on a 3d program to represent a procedural ecosystem

What is a Procedural Ecosystem in a 3D program ?
A procedural ecosystem in a #3Dprogram is a method of creating large-scale, complex #environments (such as forests, jungles, or rocky terrains) automatically using algorithms, rules, and parameters rather than manually placing every object.

I want to learn 3D modeling with the purpose of eventually maybe getting a 3D printer (or resin printer)
Does anyone have recs for programs?
Some aspects I value:
Easy to understand/get started
Preferably free OR only one time payment
#3dmodeling #3DProgram