No, it is not. You do not have a position in 3D space. You have a position on one of a small number of discrete 2D planes. BG3 is a 2D pure CRPG that happens to be decorated with 3D assets. Calling it a 3D game is the exact same unforgivable fraud as calling Metroid Dread one. It is not and does not in any way resemble it.
If you aren't strictly in real time for combat, you unconditionally cannot be or resemble an action game.
To be fully 3D, literally every part of the core gameplay physics must occur in real time. Hits cannot be determined by any other factor but the vector of the attack projected through 3D space into a character's hit box. The existence of a dice roll to determine a hit (not the vector) is an unconditional disqualifier in all contexts. There are no exceptions, and no room for them.
Everything about your description of BG3 is fully unhinged nonsense that should be offensive to any human being with any understanding of what games are. They aren't nitpicks. You're fundamentally destroying the core definition of very basic terms in a way that completely destroys all meaning. It would be less disgusting to be a flat earther.