If the pope isnt under Petrine authority I don’t know who is. There are good and bad protestant churches just as there are good and bad RC leaders and congregations.
We are talking doctrine based on Petrine authority (Credo and Catechism) and not random utterances from individuals, Popes or others. The doctrine of papal infallibility is a very limited one in a very defined context where the Pope formally speaks ex cathedra in matters of Church belief based on scripture, revelation, and sacred tradition.