Hi,
I think you are getting lost. Start with a brand new empty scenes and two cubes and get it to work there. Maybe a free falling cube fall onto another that is set to is kinematic or that is not subject to gravity for example and start from there.
be careful to properly setup your physics, you need rigidbody, you need concave colliders, you need proper physics layer matching for collisions, that's the basics, then you may ahve issues with too thin colliders and the object goes trhough in between two iterations of the physics engine and the collision is missed, it happens in cases where objects speed is great for example.
Bye,
Jean