What is more efficient for a mobile platformer, using landscape or using static meshes as a floor?

I am making my first platformer game where the camera is on the side of the player and player can only move forward and backwards with jump.

The camera will show a good chunk of the ground with some elevated positions.

So what is more efficient memory and rendering wise? Using the landscape tool and applying dirt material with ramps and erosion or just using a cube static mesh?

Is there a balance i can have between making it look good with less memory?

PS: I would also like to change the location of the camera during certain gameplay moments to give a 3D feel now and then so dont feel paper would be a good option.

Static. Always.