>> The very first mention of Peter in Rome anywhere in any writings comes from the apocryophal Acts of Peter apparently written by Leucius Charinus that was circulating at least by 150 AD. <<
St. Clement and Ignatius both make references that are pretty hard to deny refer to Peter being in Rome. And then there’s that whole tomb of St. Peter, built in the mid-2nd century. (Not to be confused with the tomb of Simon Barzilla, falsely ascribed to Simon Barjonah, in Jerusalem.)
>> I’m surprised that there hasn’t been a move somewhere in the Vatican for the sainthood of this Leucius Charinus, as he was probably the one who got it all started. <<
That’s the sort of statement which makes you come off as simply contemptuous. Besides, Leucius’ Acta are regarded as largely romantic (in the classical sense), not dogmatic or deceitful, despite certain gnostic tendencies.
Read their statements again. Neither of them place Peter in Rome.
Irenaeus's statement does put Peter there in Rome but only when Paul was there as well. But Irenaeus was also writing after the works of Leucius Charinus [the Acts of Peter] were circulating. He may have believed them and Leucius Charinus to be credible, especially since he lists a whole lot of gnostic teachers and their false beliefs, but does not list Leucius Charinus or the Acts as being among them.
We do know that Hippolytus was taken in by the fiction [romance] of Leucius Charinus and his Acts of Peter. So the church fathers were not immune from gullibility.