I genuinely don't think the 99 roll was meant to be passed
Well, if you are determined to pass a DC=99 check, you may get about 40% chance to succeed, provided that you have an advantage and a total of 4 inspiration points ready to spend.
Additionally, the game has legit ways to allow certain character builds to positively influence one or more dice rolls of their choosing per long rest.
With everything legit combined, you may get, roughly speaking, a ~50% chance (or even better???) to pass a DC 99 check.