The bottom line is if the Shroud is a counterfeit it is the best counterfeit in human history. No one has been able to replicate it.
The only way this could have been done is if you crucified a real person with the same blood type as Jesus in Jerusalem during Easter, wrapped the body in a cloth that was made with Egyptian cotton and weaved according to an ancient style, then laid in a tomb in Jerusalem, all at the same time as the crusades were going on, you would have had to use ancient tools for the scourging and you would have to get the crown of thorns and put it on his head. You would also have to crucify him the way the Romans did and not the way people thought based on artists renderings, even so you would have 1/10 chance of getting the right blood type.
But even if you did all that how do you get the image on the shroud? No one has been able to replicate that.
Finally, why would you sew the strip that was cut off back on?