What’s bothering me is that Jesus died approx. 6 hours after being nailed to the cross when it could take days for other people.
Or 3 hours, depending on how one reads the narrative.
You are not the only one who was amazed. Pilate was shocked too.
One could perhaps offer several theological reasons for the time of death, but a biological one is that the stresses of the Passion began well before the actual crucifixion. How stressed do you think you need to be to sweat blood?
Remember that Our Lord had, at every moment, the power to free Himself from pain. Each second of the Passion was willed by Him in His human nature, to conform with His Divine Will as Son and with the Father’s Will. THAT is real stress.
The stress, combined with a particularly bad pre-crucifixion regimen which included a brutal beating and a hike of some 400 meters up a hill with a 100 or so pound hunk of wood after a sleepless night enduring all kinds of mental agony, was enough to prepare His heart for danger. After this and the stresses of the Cross, and given the act of the loud yell before giving up His life, it is probable that His heart burst. This is also quite theologically fitting, not only for the poetic nature of it, but also because the same part of the heart that would have ruptured is the part that tends to show up in Eucharistic miracles, if I am remembering correctly.
There are also different ways of crucifying someone. Depending on how stretched out the arms are, or if there is a seat, or a very flat foot rest, the death can be slower. Then delirium might set in, with dehydration, hunger, the elements, or even wild animals being the ultimate cause of death rather than asphyxiation or some cardiac event.
Swoon theory is hilariously unrealistic for all kinds of reasons, some of which have been offered. Here’s another - you and I break a toe and will not walk right for a month. Jesus had open holes in both feet, and would have stayed in a cave bleeding for 2 days with no medical care, and then is walking all around. How is that realistic? Same goes for the hands and side (which certainly would be enough evidence for anyone… if you don’t react to having a spear shoved into your torso, then you are not faking anything… you must be at least comatose… but blood AND water come only from dead bodies, thus the emphasis in John’s gospel and first letter on the water).
By the way, the orthodox Muslim position is that it was a look-alike that went in Jesus’ place, not that he faked it. (How important it is then, that Thomas the Apostle was a TWIN and would have known about this kind of trick, which he probably had played with his brother as a kid! But if you can see the wounds… then it must be the same man. But there is never question about whether someone actually died.)