In terms of how I would handle it, I would choose one of these 4 spirits to work with, there’s a lot more I’m just mentioning some of the ones I use the most
Sorath can entirely destroy and burn your enemies in every way but isn’t a spirit for beginners,
Belial can break someone down and make them weak or destroy them mentally,
Asmodeus can bring a great wrath upon someone and also drain their life force by sending succubi/incubi to them,
Dra’Talon from the book of azazel can assassinate your enemies (you can not call him back after he imparts with your request).
Otherwise you can:
Do a freeze spell on them to slow them down
Cut them off from their protections and ancestors
Create thoughtforms to attack them
Attack/drain their chakras
Invoke them with a candle ritual and do any form of attack on them once invoked
I would recommend reading Angels of Wrath as well as this thread which can give you some inspiration How I tore down my targets life - Worse Than Death