Yo… what if the shrine of Resurrection doesn’t actually revive anyone, it just keeps them in a certain state for however long it takes for their body to fix itself. Like, it keeps everything there, all of the damaged body bits and doesn’t merely heal it but puts the person, specifically Link, into a stasis that keeps him alive and provides his body with the things it needs to heal but it doesn’t actually cause anything to heal, it simply keeps just enough brain function and keeps the body at just the right temperature or just puts things in the right places to encourage a healing process.
The reason it took 100 years isn’t cuz of the lack of power or anything. It’s because Link was so injured that his body just could not heal very quickly at all. Like- it takes months for broken bones to heal but even years after healing the bone may not be the same. Or if you get a sprained ankle, it may still pop or ache from time to time even decades later. Because you’re body is really only meant to hold up for give or take 80 years, and that’s only with modern medicine or just dumb luck. But Link likely suffered a great number of injuries, many of which were internal injuries, like to the lungs, heart and other vital organs, and those kinda of injuries can also be irreparably damaged for years and may never even function the same after they’ve been healed.
So like— 100 years to heal all of that… and considering it was likely just his body doing all the healing and not the shrine doing anything other than keeping him in that unconscious but alive state it makes sense. It makes sense that it would have taken that long.
And that’s pretty interesting because it doesn’t say anywhere that the shrine actually heals anyone it just puts them in stasis and prevents them from dying. Which may also result in sleep paralysis.