As someone who has created PIP plans in my career, it sounds like they want you out. Chances are they know your historical performance, and it sounds like a pretty bad PIP plan.
Unfortunately, some companies create PIP plans as a way to get rid of employees instead of using it for good to help develop them. At the same time, if you don't like your work and are not hitting required numbers, it may be in your best interest to leave anyways!
I suggest holding your head up high and finishing out the month but not exerting extra effort/going above and beyond average if you already decided to leave. However, it would be wise to start getting in touch with recruiters to help the job search, update resume, reach out to old mentors, and begin applying to jobs. Goodluck and feel free to DM for advice!