"Speculating on this matter". There is no speculating in the Church of Rome, because once the "Holy Fathers" have spoken, the matter is settled, there is no more debate. And this matter is settled history. Both Jerome and Eusebius put it to bed. Jerome clearly writes: "Simon Peter . . . pushed on to Rome in the second year of Claudius to overthrow Simon Magus."
What is there left to "speculate" about. Holy Father Jerome says that Simon Peter went there not to preach the Gospel but in order to overthrow Simon Magus [Simon the Magician]. Was Saint Jerome mistaken? Surely the Holy Fathers are never wrong.