The worst case scenario is not taking the offer then getting let go for performance, which means zero severance, health insurance terminated same day.

That's generally not legal in the U.S. or most of the EU. The company would have to establish a very significant paper trail to establish that these individual "performance-based" layoffs were not part of a layoff subject to WARN regulations (or their European equivalents which are even stricter). The hurdle is so large that no company has successfully pulled off such a feat, and many of the companies that tried ended up paying significantly more in penalties to their local Depts of Labor than they would have saved with this stunt.