Yet it is equally plain to me that he is talking about the proper exercise of authority and not a denial that one can exercise such authority. I notice that you did not address the fact in in Mark our Lord affirms that someone will indeed sit at his right and his left. As for your attempt to conflate the keys with the power to bind and loose, we will just have to disagree.
Mat 18:18-19 " 18"Truly I say to you, (D)whatever you bind on earth shall have been bound in heaven; and whatever you loose on earth shall have been loosed in heaven.
19"Again I say to you, that if two of you agree on earth about anything that they may ask, it shall be done for them by My Father who is in heaven.
The keys are directly related to the power to bind and loosen, and that is granted to all his disciples, not just Peter. And it is clear that it takes at least two, not one, to get anything "approved" by God (notice it's not the Son, but the Father — again suboridnaitonalist).
So, no, he definitely did not appoint Peter alone as the sole authority in the Church. It takes at least two of any of the twelve.