Move Character Through Z and X Axis Simultaneously

Hi All, I'm building a 2.5d beat'em up game. I have an environment in which the character needs to travel through the Z axis at certain parts of the game but most of the time it will be restricted to the X and Y axis.

I thought of two possible theoretical solutions.

A. A script that when character controller passes over object A, it travels forward on z plane. The script would be attached to the game object that the character controller passes over.

Or

B. A Script attached to the character controller which keeps it a certain Z depth from objects behind it. Not sure how this script would react to other enemies, or how it to identify what objects it stays above.

I need some help of how I would go about doing this. I'm an illustrator attempting to make a game, so the scripting side is a steep learning curve. Total Noob.

Thanks for any help!:)