I am being real.
He still was close to death/defeat (he believed he could die from Hollow Purple, and that may still be true as he was never directly hit by it and just being in the radius injured him badly). The extra life isn't an automatic skill activated upon dead: it's just a one time heal extremely situational to this one only time in his life.
That "extra life" can at most be called an asspull but it's far being from a Gary Stu thing, and not something he would have had access to had the fight taken place under any other context, and not something he will ever again have access to. What we saw is precisely the fight without it and he did get nervous and scared near the end, once again, by the second time he was outsmarted.
The "extra life" changes nothing about his actual skills, techniques and weaknesses as a character/fighter.
If it did not change anything, why he switched to it now?
Go on, keep the same energy and die gracefully.
It is dumb to think that it did not change anything when he went into the gamble knowing full well that Uraume had 4 fingers and there was one in Gojo's possession.
If he failed to take over Megumi's body, he would still have been fine. Because Uraume could find another vessel or waited for another millennia or whatever.
He ALWAYS had options. There was no risk involved.
He said HP can be fatal, but judging from the damage it did, it was insignificant. Either HP was nerfed or Sukuna's durability is off the charts. Something does not add up here.
Then again, he fought 3v1 against Gojo. Had Mahoraga infront of him all the time as shield.
There was no way he could have lost. Even if there was, Gojo would not have killed Megumi with his own hands.