If they don’t fulfill their end of the agreement (paying until the date in question) then surely any agreement to quit in return for X months pay would be broken? So you’d still be employed unless the pay out is made?

This is where I go ”I know nothing about US law but if I wouldn’t win this argument in any court even without representation then it must be fundamentally broken”

The argument would be ”those who entered the agreement didn’t have the authority to do so” but obviously that can’t hold water.