The Bible claims Pilate marveled https://biblehub.com/greek/2296.htm that Jesus was already dead late on the afternoon of the crucifixion (Mark 15:44).
And Pilate marveled if he were already dead: and calling unto him the centurion, he asked him whether he had been any while dead. 45- And when he knew it of the centurion, he gave the body to Joseph.
Why? Pilate had Jesus scourged (John 19:1) with a full Roman scourging...
Then Pilate therefore took Jesus, and scourged him.
Pilate saw him in person after that (John 19:5).
Then came Jesus forth, wearing the crown of thorns, and the purple robe. And Pilate saith unto them, Behold the man!
Based on what I have read about a Roman scourging it was not uncommon for a person to die during or shortly after a Roman scourging (https://www.bibleversestudy.com/acts/acts22-roman-scourge.htm). Pilate knew what shape Jesus was in. After all, he saw him AFTER the scourging. It was possible to survive a crucifixion for two to three days for someone who was in reasonably good shape but Jesus was beaten to a pulp and died a few hours later. So why was Pilate surprised?. Jesus was no doubt greatly weakened, probably fatally, by the beating itself. The crucifixion itself was a horrible way to go https://gizmodo.com/this-is-the-horrible-way-that-crucifixion-actually-kill-1477804826