The single worst member of the X-Men is actually one of the best in the franchise's new Krakoa era, and could easily be one of the strongest mutants in Marvel Comics. The mutants of the Marvel universe went through truly difficult times in the 2010s, both in-universe and in a meta-textual sense. But ever since writer Jonathan Hickman's line-wide reboot, one Bailey Hoskins can finally be a part of the team he's admired for his entire existence in the Marvel Universe.
In the 2010s, the mutants were in serious danger of becoming extinct - or at least, taking a backseat to another marginalized group. At the time, Marvel was pushing the Inhumans into the mainstream via multiple comics series, their inclusion in Agents of SHIELD and an Inhumans series airing on ABC. An infamous series known as Inhumans vs. X-Men ended with the X-Men definitively losing (it didn't help that the Terrigen cloud that gave Inhumans their powers was now toxic to mutants). But all that changed in 2019, when a soft reboot gave the X-Men not only a home of their own, but a method to return to said home after death.
In the series Worst X-Man Ever, Bailey Hoskins is an ordinary human, or so he believes. His parents eventually reveal they are mutants, and take him to Xavier's School for the Gifted to see if he has powers as well. Unfortunately, Beast discovers that Bailey has the power to explode - just once. He can't reconstitute himself after the explosion and will die if he ever uses his mutant power. The rest of the series depicts Bailey's attempts to fit in with his fellow mutants, knowing he can never help his kind in battles or even in general life.
However, with the reboot allowing mutant resurrection, Bailey can use his power multiples times without worry. The Five mutants in charge of the resurrection protocols would most likely bring Bailey to the front of the queue (considering he can't use his power without dying) and could potentially learn to control his ability after practicing in such a manner. Cerebro would be instructed to back up his memory quite frequently, since Bailey would not only undertake dangerous missions, he would be the only X-Man who is actually expected to not return - at least in the tradition sense.
It's worth noting that Bailey Hoskins has actually returned in the X-Men reboot, in a sense. While Worst X-Man Ever was written out of continuity to begin with, the 616 version of Hoskins was tragically killed in a Sentinel attack on Genosha. However, he was transformed into a zombie and since the zombified version of him is technically dead, Bailey Hoskins was resurrected and now lives out his days on Krakoa. Perhaps the "Worst X-Men Ever" may yet turn out to be the best - or at least the luckiest, thanks to Krakoa.