Which church in the entire city of Galatia did Paul point the city to as a "model church". Right, not one. I highly doubt that Paul would recommend ANYONE to attend any "Christian" church in the entire city of Galatia.
And would Paul tell someone that if they didn't attend the "church" in Corinth that they'd be in trouble? I doubt it, for he'd probably tell EVERYONE to run from that church, for they were proud of the man that was having intercourse with his own step-mother, and by this, Paul questioned whether or not anyone in the church even had the indwelling Spirit to judge and handle the problem.
Paul would tell EVERYONE that they're better off staying away from Corinth and the entire city of Galatia.
Each city had only one congregation. Every Christian in Galatia belonged to that one congregation. Every Christian in Philippi belonged to that one congregation. Every Christian in Corinth (and apparently those in Cenchrea as well) belonged to one congregation.
Where do you get the idea that Paul warned people away from any of them? Certainly not from any of the letters he wrote to those churches, which contained both encouragement and admonishment.
The Christians in those cities depended on each other for their very lives and livelihoods. In those days--as in many areas of the world today for Christians--a person's entire life was bound in his connections with family and community. Without family, a person would fall into destitution and likely servitude, like the Prodigal Son. But family was also bound into spirituality. Family life, social life, business life all revolved around the local spirituality. Feast days, temple days, holy days--those marked time, marked relationships. Without them, there was no life.
But Christ demanded Christians to walk away from all that. To us it's just a theoretical kind of thing, but to those 1st century Christians, it was as real as rain. If they had to stop pagan temple worship and pagan holy days, that meant rejecting family and friends. It meant rejecting business and social relationships:
Because of this, they consider it strange of you not to plunge with them into the same flood of reckless indiscretion as you once did, and they heap abuse on you.
The Body of Christ is intended to replace those worldly relationships.
"Truly I tell you," Jesus replied, "no one who has left home or brothers or sisters or mother or father or children or fields for me and the gospel will fail to receive a hundred times as much in this present age: homes, brothers, sisters, mothers, children and fields...."
I have a friend who became a Christian at the age of 14 in his native country of Mali. But his family was Muslim. His father chained him to a tree in their back yard and his mother tried to poison him. Fortunately for him, she had sent the poisoned food out with his brother. His brother--not knowing it was poisoned--tried to join into the abuse by eating the food himself.
But that's what happened to those Galatians, Corinthians, Romans, Ephesians,
et al, when they became Christians. They were cast out of their old relationships and had to depend on each other.