It’s not so much a matter of which church is to be followed. It’s more a matter of following Jesus: believing what he believed, taught and lived.
However, part of following Jesus means we will join together with other people who are also following Jesus (e.g. 1John 1:1-4; Heb. 10:23-25), and it’s when we join together with these other Christians that, together, we are the church (e.g. 1 Peter 2:5).
Because we are trying to follow Jesus and learn from him, it matters what we believe about him and his Father and the gospel he and his followers taught, and it matters how we live (otherwise we aren’t really following Jesus). Some people in Paul’s day were trying to teach a gospel different to the real one, were distorting the gospel (Gal. 1:6-7), were trying to teaching untrue things about Jesus (2 Cor. 11:4), and Paul said this sort of thing was no good (Gal. 1:8-9). So, when it comes to belief in the gospel, it matters what we believe; and, when it comes to which church we join, it matters what the church as a whole believes. What we need to do is believe the (actual) gospel and then find and join with people who believe the same.