Hey, well, the nice thing is that there may be other details you missed for Shadowheart’s romance, that you can play now. Minor spoilers for acts one and two:

Shadowheart has three small interactions that are pretty cool. In act one in Grymforge, you can give her an idol of Shar that you find, and especially if you’re a cleric of Selune, she has a unique reaction. However, that interaction has been mostly broken since patch 4. You can also give her a night orchid in act two, which is cute, and you can give her the Noblestalk mushroom from the Underdark to help her recover one of her memories, which does give you some unique scenes/content.

You should also be sure to long rest a few times before you even get to the druid grove in act one, because you get more interactions with her. Also, you should long rest after you’ve spoken to Nettie and before you leave the Grove, and you get other potentially really cute dialogue. Playing as a cleric of Selune also works best when you’re romancing Shadowheart.