‘The early church was not protestant’ ... a nonsensical assertion if ever we’ve had one at FR! But the unspoken inference is also absurd, that the early church was the Catholic Org.
Our FRoman friends like to presume that "their" church was the original one from Apostolic times. The word "catholic" - meaning universal or of the whole - first came to be used of the faith of the early churches in the second century. What started out as a adjective describing the faith of believers was co-opted by the Roman church when Christianity was no longer under persecution and became the state religion. Genuine "catholic" churches are those that teach and believe the same tenets as the early church did - those which the Apostles set up.