resources for learning 3d? (environments) (not the basics)

Hey! I have tried and failed many times to create 3d game environments and am looking for any resources people might have found helpful when learning this.

I've seen many beautiful environments like this and tried to copy them, but whenever I do it looks terrible. I get lost in all of the settings and adjustments and can't get anything that looks right.

I've been painting for a number of years now and can see the art that I want to make in my head, but I just can't make it happen in 3d.

Has anyone else struggled with the same thing? If you have any tips or can recommend any resources I'd love to hear them!