It is ultimately up to you to decide whether or not to kill Paolo in Dishonored 2. As a player, you have the freedom to choose your own actions and play the game in a way that aligns with your personal values and beliefs. If you prefer to play the game in a more peaceful or non-violent way, you may choose not to kill Paolo.
On the other hand, if you are comfortable with making more aggressive or lethal choices in the game, you may decide to kill Paolo. It is important to consider the consequences of your actions and how they may affect the game’s story and your character’s reputation.