Varys already tried a secret assassination plan. The point was that it needed to be Jon bc no one else could get close enough to her as well as past Drogon. Arya would have been s’mored.
OAS, one of the many things that annoys me about Bran is how he functions as a moral arbiter. Both Theon and Jon looked to him for personal forgiveness but Bran had to go the ‘everything you did brought you here where you needed to be’ route which is 🤢.