Turn based and action are mutually exclusive. It is not and does not resemble an action game.
The assets are 3D. You do not play in 3D. You do not cast a spell and have the physics of your interaction calculated in real time while 10 other characters are simultaneously acting and having their spells calculated based on the real time movements of all the other characters. You do not hit a jump button and have where you land determined by your speed and direction. The actual gameplay mechanics are all pure dice roll. There are no 3D physics in play.
The absolute bare minimum:
Your jump must be decided by the vector of your movement when you hit the button. If it is not, there is literally nothing you can do to qualify.
Your actions must be aimed in real time and the outcome determined by the vector of your aim. Hitscan is shit, but it can qualify. If the action (not the vector of the shot) is decided by a dice roll, you unconditionally do not qualify.
There’s plenty more. But BG3 is not and does not in any way mechanically resemble a 3D action RPG. It has no common traits. The camera perspective outside of combat isn’t relevant.
I think you’re simply misunderstanding what “3D” means. 3D does not mean real-time, dynamic, or anything else. It simply means 3D. BG3 is entirely in 3D. Every single asset is 3D hell the entire explorable world is 3D. So yes, it quite literally is a 3D game. With action. Making it a 3D action game.
Think of what the alternative would be. Is this a 2D action game? Obviously not.
If you’re looking for a 3D real-time action game then yeah, this isn’t that. But that’s not what anyone’s arguing.
Edit: Also… is your argument that a game like Morrowind isn’t in 3D? Just because hits are handled by dice rolls? That’s insane lol.