That's fair. I just remember being very frustrated that felt like a basic feature I was implementing per the tutorial broke immediately in such a fundamental way in such a simple situation, and not being able to find any sort of explanation or solution at the time. Possibly it was fully my fault and the info was readily available!
I think its really just the trappings of game development being full of tribal knowledge.
The tutorial probably should have instructed you create box colliders for walls (giving a greater area for the physics engine to catch collisions) rather than a simple plane/quad which would lead to the exact issues you had, or at least explained why a box works better than a plane.
I guess you have to balance the necessary information with overload in your tutorial or at least have an aside or additional reading that really helps understand many of these internalized understandings.
