The first picture is made of 2 shapes, a cone and single torus(as the base ground.)
The second picture is made of 3 shapes. I scaled a Torus as the base ground for the cave columns. The columns were all made of 1 cone shape used with basic transformations. The plants were all made from a cube that was created into 3 variations of the same plant. Then just played around with light.
In the viewport, Eevee lighting looked good but rendered much brighter. Cycles was closer to Eevee’s render mode.
Didn’t bother cleaning up collisions, there were so many because I cloned a lot of plants for rotating and placing around. Though it pains my perfectionist heart to say good enough and move on. Had to stop testing various lighting setups and additional render testing. Ugh. Huge rabbit hole. LOL