What’s with the building bit? No one is saying the Church is comprised of buildings.
When you take it to the church, which one do you go to?
If St. Paul were today to decide to go to the Church in Corinth, where would he go?
Again, I don’t see how anyone can read Scripture and conclude Jesus and the Apostles were establishing a plethora of individuals with different doctrines without any authority other than their own.
The authority is God's through Scripture. There are not nearly so many different doctrines as the Catholic church likes to paint others as having.
1 Corinthians 12:4-20, 27 4Now there are varieties of gifts, but the same Spirit; 5and there are varieties of service, but the same Lord; 6and there are varieties of activities, but it is the same God who empowers them all in everyone. 7 To each is given the manifestation of the Spirit for the common good. 8For to one is given through the Spirit the utterance of wisdom, and to another the utterance of knowledge according to the same Spirit, 9to another faith by the same Spirit, to another gifts of healing by the one Spirit, 10to another the working of miracles, to another prophecy, to another the ability to distinguish between spirits, to another various kinds of tongues, to another the interpretation of tongues. 11All these are empowered by one and the same Spirit, who apportions to each one individually as he wills.
12For just as the body is one and has many members, and all the members of the body, though many, are one body, so it is with Christ. 13For in one Spirit we were all baptized into one body— Jews or Greeks, slaves or free—and all were made to drink of one Spirit.
14For the body does not consist of one member but of many. 15If the foot should say, "Because I am not a hand, I do not belong to the body," that would not make it any less a part of the body. 16And if the ear should say, "Because I am not an eye, I do not belong to the body," that would not make it any less a part of the body. 17If the whole body were an eye, where would be the sense of hearing? If the whole body were an ear, where would be the sense of smell? 18But as it is, God arranged the members in the body, each one of them, as he chose. 19If all were a single member, where would the body be? 20As it is, there are many parts, yet one body.
He may have been at someone's house...Likely tho, he was in the open field at that back end of the farmer's market...Bible doesn't tell us there was any particular church building in Corinth...As was stated correctly, the church is not a building...