Yeah that quote from Francis was borderline apostacy he was not a great pope in my opinion I pray he is in heaven.

The Catholic church has her authority from Jesus Himself when he told Peter that he would build the church upon him and Peter would hold the keys to heaven. That's why it's based, it's based in Truth which is incarnate in Jesus.

A pope speaking personally, not ex cathedra, is not making a binding statement of the faith, but rather giving an opinion. An opinion that is not congruent with the faith in my opinion. Had he been speaking ex cathedra then yeah it would be a major crisis and would question the authority of the church. Never gonna happen though since Jesus Himself promised the gates of hell would never prevail against the church.