Shin is not
currently having a near death experience though, is he?
Kyoukai’s spiritual revival technique must at bare minimum, heal or partially heal the body of the recipient of her life energy or else they would just die again from their wounds, would they not?
The point of those examples was not anything to do with near death/death/whatever. It was to do with physical condition and their ability to fight despite being physically compromised.
Even if we remove every single example that died from the wound I described, that only removes Ouki and Choutou.
Moubu fought on immediately after an extreme diff fight and a broken wrist, that Mangoku soldier did not die on panel, Mougou got back up after losing an arm and Duke Hyou was not killed by losing his arm, he was killed by getting cleaved in half.
Shin has no lost or broken limbs, no grievous injuries, is not physically compromised and is clearly not dying.
Why should he not be able to fight when people with broken or missing limbs (e.g. Hyou, Mougou and Moubu... oh, wait. Just remembered papa Gyou’un and his speared arm. Lol) or are in the process of dying (e.g. Ouki and Choutou) can fight just fine?