Unless you can afford to be unemployed for an extended period of time or this is your path to retirement, I recommend taking the demotion. Some things to remember…
It’s easier to find a job when you have a job. Outside employers don’t need to know you were demoted. As in typical Nike fashion, the organization will be in complete disarray for the next 12 months so you can do the bare minimum just to get by. if you have unvested stock, you’re leaving money on the table by exiting. Use the Nike Nike has used you.