Here is the official 5e rules for fall damage if your curious.
Falling
A fall from a great height is one of the most common hazards facing an adventurer. At the end of a fall, a creature takes 1d6 bludgeoning damage for every 10 feet it fell, to a maximum of 20d6. The creature lands prone, unless it avoids taking damage from the fall.
I haven't noticed anyone falling prone from falling. Likewise I haven't noticed anyone rolling to not taking damage. So im not sure exactly how they are working out the damage in bg3.
