She was a damsel the whole last 3 episodes. Literally, David and the crew sacrificed everything to get her back. Is it her fault? No, but it was the only thing she added to the plot outside of protecting David from the shadows which she immediately failed at once David's plot needed to be moved forward.

David was her blind spot regarding all her beliefs which is intriguing, and their relationship became a very predictable trainwreck because Lucy from Act 1 was night and day from Act 2. David is also guilty of not growing much at all.

The show needed 3 Acts something in between the current Act 1 and Act 2 to add context to Lucy and David and their downfall.