Something similar was suggested back in 2017 by someone else but doesn’t seem to have gotten any traction. I began my game dev journey in the hope of being able to make a 3D platformer and I still very much want to do it.
The course could include one or two completed levels that cover topics like moving platforms, unlockable areas, unlocking new abilities (eg. Fire Mario, Starman, Wing Cap), swimming, swinging on grapples or vines, patrolling enemies, various means of terminating enemies, checkpoints, and perhaps most importnat of all, a SAVE system.
Based on my own experiences trying to make one on my own it should probably be an intermediate or even advanced course that presumes you know how to download Unity, set up version control and are fairly competent in C#.