Hey! So the camera itself does not effect collisions. Height maps might be a bit complicated if you are just starting out. Collisions in general can be quite daunting in programming. Considering also that GM is primarily a 2D program makes this even more daunting of a task. I have covered how to make 3d collisions from scratch if you are interested in learning more Here if you are interested. I would, however, recommend that if you want a program that already includes basic collision functionality, physics, and the like then a program like Unity or Godot would probably be a better fit. :) I am mainly making these assets as a basic template for GM developers to play around with and learn basic 3d concepts. This is not a full 3d engine (hence the 'faux' part of the name). You can also look into ColMesh by thesnidr for a more robust 3d collision system! :)
I hope this helps! :D