Let's forget the word "Catholic" for the moment. Some church has to make a claim for truth, or Christianity becomes a nonsense, right? At least one Church must have preserved the whole truth intact.
So how do we determine which it is? The Church with the fewest sinners? The least scandals? That's a very shaky proposition. We're heading into murky waters here. As a billboard I saw yesterday said: "Church is hospital for sinners not a sanctuary for saints" (it was a Methodist Church, BTW). Aren't all our churches full of sinners?
Thyatira was an unrepentant Church. Obstinate in its sin. From where I sit, that adjective applies to certain groups in every church but not necessarily to the churches themselves. There are groups who want to change church teaching so as to remain comfortable in their sins. And in some cases they've succeeded. A good example would be the Episcopal Church and the homosexual issue. Now that is a Thyatira style Church.
Catholic teaching about the sinfulness of sodomy is clear and unchanging and we're trying to clean out the trash. Big difference.
Not so.
There were 7 churches mentioned in Revelation. All of the Christians within them combine to form the Invisible Church that includes the great cloud of witnesses.