The Historical Jesus is real and He rose from the grave

[Minimalist]

Yes, according to the tradition, he requested it.

But only according to tradition, which essentially is worthless.

The so-called First Epistle of Clement - most likely a later church forgery - is the only mention of the death of "Peter."

1Clem 5:4
There was Peter who by reason of unrighteous jealousy endured not one
but many labors, and thus having borne his testimony went to
his appointed place of glory.

Note that it not only does not say he was crucified upside down...it does not even say he was martyred. It just indicates that he died.

There is a line in Josephus however in which he notes that Roman soldiers, when the got tired of crucifying jews in the standard method, did nail them up in unusual positions. The author of Acts would have been in a position to know of this writing and perhaps indulged in a little more fanciful writing.