According to PHB
- You can only do a sneak attack with a finesse or ranged weapon.
- You have advantage OR there is an enemy of your target near the target and you do not have disadvantage.
- You have one SA per turn
That means you have only one SA even if you have several attacks per round (dual wielding, haste, multi classing).
You can do a SA again if the enemy provokes an AoO on the enemies turn.
All of this is assuming BG3 follows the PHB rules, I am not sure if they do.
I am OK with passive SA if it means: "You deal extra damage the first time you hit something with an attack during this turn if the requirements are met."

Prof. Dr. Dr. Mad S. Tist

World leading expert of artificial stupidity.
Because there are too many people who work on artificial intelligence already