Everyone must obey the authentic Papal Magisterium: what was taught by all of the present pope's 265 successors going back to St. Peter and even to Our Blessed Lord. Even the pope is subject to this chain of transmission, because he is to conserve and hand on the "Deposit of Faith": he is one who safeguards the doctrine and passes it on: a servant, not a master, of true doctrine.
Listen: if the present Pope deviates from the Papal Magisterium --- not handing on to us what was handed on to him --- then who/what do you suppose we must we obey: the Magisterium, or the Pope?
We Catholics should know better than to make an idol of a derelict pope.
One of your fellow RCs suggests papal infallibility took 1800 years to “develop”. That’s quite a bit of time don’t ya think? ~1800 years?? Really?