You are so right. Alec and Magnus are too cute. I love how they are starting to find their rhythm as a couple and how they support each other.
What is noticeable with Clary, is her ability to fight. In Season 1 when Alec was training her, she could barely hold her balance. With the fight scene with Jace, she looks like an experienced fighter and she held her own against Tim.
This episode definitely feels like a first episode of a season where they close off the previous season and set up new storyline. New villian and poor Jace still suffering.