She has those memories yes, but nothing indicates those are true memories. She even pops approval from selfless actions.
We know from the dark urge that
the nautiloid has been putting people on ice for at least 15 years and doing who knows what else to them
Fan theories are kind of irrelevant to the conversation. If I'm a newish player playing a good guy and choosing my romantic partner I'm not going to know Shadowheart might be operating on incorrect information about who she is. What is important is that, as far as she knows, she's trying to help Shar in whatever probably nefarious scheme she's cooking.
