See Invisibility in BG3 isn't guaranteed to work.
An invisible target rolls a DEX save (DC 15 IIRC) each time it's the turn of the person with See Invisibility (If they're close enough to them that is) and unless they fail the roll, they remain invisible.
As such it's often more effective to simply throw out some AoE damage like tossing a Alchemist's Fire, dropping an AoE spell like Ice Storm/Wall of Fire, or using some ability like Radiance of the Dawn. As damage will break invisibility more consistently than See Invisible/Faerie Fire's saves.