I'm trying to see if I can find one of my older posts on the BG3 board about my experience with playing as origin Shadowheart.
But it largely came down to the fact that in her pivotal moment, it had a lot less meaning to me, because I can't possibly care about Shar and the related dilemma in the way that Shadowheart herself does. But when she was my companion and was an agent of her own thoughts and actions, it was more impactful because all I could do was influence her, with the choice ultimately being hers to make.
I equated playing as origin Shadowheart to Homer trying to decide whether or not to press a button.