From what I have read and seen, I “believe” that the Shroud of Turin was the burial cloth of Jesus Christ. And it bears witness to the miraculous event known as the resurrection. But I could be wrong.
I believe in Jesus Christ, who is risen from the dead.
But agreed - belief “in” a thing such as a a chunk of wood or a piece of cloth is not right.
“belief ‘in’ a thing such as ... a piece of cloth is not right.”
I bet the people who were healed by Paul handkerchief (Acts19:12) might disagree with you. The woman with the hemorrhage touched the hem of Jesus’ robe and was healed. Peter’s shadow healed (Acts 5:15).
I’m not saying that one should worship a handkerchief, a robe, or a shroud as objects. But items connected to holy people can be venerated.
I agree with you with one caveat. For me it is immaterial if the Shroud dates from the Middle Ages. Ultimately, my Salvation is not dependent upon a length of cloth.