It's crucial to assess your situation thoroughly. Ask yourself if you can realistically address the points outlined in your performance plan and whether doing so will positively impact your relationship with your manager. Consider whether your manager is resolute in parting ways with you, and if so, if there's anything you can do to change their perspective. If your performance metrics are solid yet you find yourself on a plan, it likely indicates a deeper issue unrelated to your numbers. Remember, it's not personal; your manager's decision might be driven by team dynamics rather than your abilities alone.
My suggestion is to proactively begin exploring new opportunities. Seek out a company and a manager with whom you resonate better. Remember, your current situation doesn't define you, and there are plenty of other avenues where you can thrive professionally.