I'm afraid the only similarities to D&D I see in BG3 are mostly cosmetic. The names pf the character classes and spells.

The entire combat system in BG3 has virtually nothing to do with D&D's mechanics. It's all about height advantages and environmental effects. This puts melee classes at a SERIOUS disadvantage as they have to be at the same height as their target and will almost always be subject to the same environmental effects at their target because they have to be in melee distance.