The Bible, yes, shroud stuff, no.
Well, I don’t see why anyone should accept your pronouncements about it.
Many wise people - of Christian faith, of other faiths entirely, and of no particular faith, have studied the shroud and been deeply puzzled by it. But we’re supposed to believe you and not them, even though you haven’t studied the matter?
The Christian narrative states that Jesus died, was buried, and rose again, and you apparently believe that. What would be at all ‘unChristian’ about the fact that a material item from those events might have survived?
There are a lot of things Jesus never bothered to mention; that doesn’t make them untrue.