Severance offer, what should I ask for? - what worked for you?

I was offered 10 weeks of severance after 10 years as a hotel front-desk agent, and I have a few days to sign. I am in Phoenix, in case local advice matters. There is a non-disparagement clause. Did anyone negotiate and succeed?

Ask for the offer in writing and do not sign on the spot. A day or two to think is normal.