language evolves. How the creator of a word pronounced a thing is irrelevant. Witness essentially every word in the English dictionary. None (possibly literally) of them are pronounced as they originally were (frequently not spelled as they originally were either) unless they are _very_ new.

the "correct" pronunciation is whatever the community decides, despite what we may individually think of it.

As such "jif" is decidedly _not_ the "correct" pronunciation because essentially the entire community says "gif"

"jif" would be the "archaic" pronunciation. Technically valid, but not used by anyone except for hold-outs and people who refuse to accept modern pronunciation standards.