Edge is new, so it was an obvious target and MS can learn from those contests, FF will be the next preferred target because the implementation of a sandbox on v54.
It is not Palemoon that is criticized but any browser with the FF core, it was always weak compared to Chrome .
I hope the new sandbox will be effective, i checked some of its mechanism, it is based on levels of tightness, 0 - 1 - 2 , 2 being the highest one, i saw a Level 3 but , very tight but it seems it will not be implemented yet.