[circlecity]

"A specific office that already existed."

where in the text does it say this? Nowhere. Where in the text does it say Peter ever occupied such an office? Nowhere. You just made it up.

[vladimir998]

You wrote:

“where in the text does it say this? Nowhere.”

Actually it’s right there where I quoted the text.

“Where in the text does it say Peter ever occupied such an office? Nowhere. You just made it up.”

Nope. Obtained the episcopate.
The episcopate is a office. If he obtained it rather than founded it, then it already existed.