I am writing a fantasy novel in which I want the main character to die right around the middle of the book, only to resurface later with unexpected powers that apparently kept her alive -- something which should come across as a shock. I realize that bringing a character back so easily like this can take a lot of the emotional weight off of the many other, real deaths that happen in the story, and I don't want any of them to feel less of a hit because there is the possibility that the character might just pop back up alive.
There is a rather heartbreaking (real, irreversible) death at the end of the story that comes across as a huge shock, just like the MC's death midway through. But the first thing I thought when reading it back was "well, who says this character doesn't have the unexpected powers too, can't they just come back?"
This is a problem faced by comic books and extended universes where beloved characters die off, only to be "reborn" or rebooted because they are so loved. This devalues every single time a character dies because you know they'll probably be back.
How do I avoid this and make this one fake death clearly the only fake death and/or treat the real deaths differently so that they hit harder?