If you’re asking about making assets from which you construct environments… you’ll be using the best tool for the job, there is no 1 best tool for all jobs.
Have a look at Blender, free, universal and has a welcoming community. Think of Blender as of a general tool; but if you wanted to specialise and make great looking…
trees
water shader
hard surface boolean ops
landscapes
pixel art backdrops
ambient sounds
normal maps
…there will always be a tool / plugin that does it better. Because it’s designed to do that one thing. For example:
Environments can mean too many things to get a single answer.
Most here will think of it as the scenes you build for the game… some will think of it more as the lighting… and some will think of it as nature components like trees and maybe even sounds.