>>287325205
I'm just gonna reply to this with various solutions I'm finding online 
https://forum.unity.com/threads/questions-on-stacking-physics-objects.369993/
"If you're using the "Freeze" constraints on the Rigidbody you might need to increase the (Edit->Project Settings->Physics) Solver Iteration Count to 30. Avoiding the Freeze constraints all together might also remove the problem."

It seems to me like you want to make use of rigidbodies and freeze the constraints, I'm 99% certain that's how the world I linked to you works, because the tiles sortof move when you drag a tile into them, then snap back to where they were.

So yeah rigidbodies and freeze constraints.