3d SideScroller platform concept

Hello everyone!

I am making a 3d side-scroller where a character is simply jumping from platform to platform. It would be something similar to "Mario" or "Sonic".

However instead of jumping from platform to platform in a straight, linear fashion. I would like to have multiple platforms at different Z-depths where the character would transition to the platform automatically when they jumped.I still would like the camera to have the traditional front facing view like other side-scrollers but I would like to incorporate that z-depth platform system. I would also like for it to be a soth transition as well if possible.

attached should be a small concept of what Im trying to do.

I am simply asking for an approach solving this coding. I would be incredibly grateful if anyone pointed me in the right direction on how to take this challenge on. I have tried several with like using gravity and automatically offsetting the jump but nothing is working.

Again im just asking for any hints or suggestions as i would like to learn from this. Thank you very much for your time!