They praise BG-3 vertikality ... And yet, i had several prooves that game dont understand Z Axis at all ... and many damages and effects affected several of my party members, even tho each of them was on different floors, or just high. I certainly hope this got fixed!
If that can reassure you, Fextralife told us that verticality will be more present after early access zones :
He is most likely talking about the mountain pass exit I think.