There is a difference between substance and property. The divine substance (epiousios) in the Eucharist has no relation to its host which maintains the properties of bread. Think of this as an encounter with the Jesus in the first century. Although He was 100% man and 100% God there would be no way for you to scientifically or forensically establish His divinity.
Peace be with you
“The divine substance (epiousios) in the Eucharist has no relation to its host which maintains the properties of bread.”
Exactly, as the divine substance of God’s Word has no relation to the paper and ink, which maintain the properties of paper and ink. The bread is the body of Christ, Christ is the Word, and the Word is the bread of life. Those terms are not coincidental or inconsequential, but direct analogs, pointing to the same divine being, Jesus Christ.