I am not sure if BG3 recognises "layers". [...]
I worry it is a result of bad decisions made early into development though, and will be here to stay.
I am equally unsure. The game world is technically 3-dimensional, but much of the programming and systems are strongly
2-dimensional.
And I am equally worried that we will see little significant progress on verticality, and that this will go down as one of Larian's questionable descriptions of their game, and coming up short of what was advertised.