Boss Changed My Job Description And 1.5 Weeks Later Said I Dont Meet The Job Description Requirements.

Just as my title says, I got 2 options provided to me. I got a new boss and the whole org became a mess.

1 - I go on a PIP for 4 weeks and no severance even though i had a 4.8/5 performance review 4 months ago.
2- I accept severance for 5 weeks for working 3 years and mutually separate. Other employees previously got 12 weeks even for just working 2 years. I tried to negotiate and they said this is non negotiable.

I kinda saw this coming but I didnt think about legal help before this. They were pressuring me I had 24 hours to make a decision.

The only 2 screenshots I have are the day of the job description change (which I was notified of and agreed I will make the changes in my role), and the email saying I no longer qualify for my position after mentoring, coaching, etc even though there was never any mentoring or coaching for my position.

I already signed for the severance package, but nothing in the terms tell me I cant sue them. This happened just 3 days ago so I'm trying to gather more information on what I can do.

Only 2 documents I salvaged but that's it. Is this worth fighting?