Sure it is. Every Catholic on this board says that.
....the early Church Fathers up until Constantine identified themselves as Catholic,....
Show us where they use the term. Where is it found in Scripture?
There was only One, Holy, Catholic and Apostolic Church then. Denominations were invented in the 16th century. The seven “churches” in Revelation were not seven denominations!!
The only true church is the real believers regardless of denomination. The Catholic church is not the true church.
the Church doesn’t “claim” it, it’s a fact of history, if you ever read the Fathers you would realize it.
the term “Catholic” is not in Scripture, much like Trinity isn’t either. But the One Church founded by Jesus is in Scripture and the term was begun by the pupils of the Apostles to distinguish the true Church, from other pretenders such as the Gnostics. Any one claiming to start a church is no more the Church, than someone claiming to be the President of the US, if they haven’t been elected.
Show me where “denominations” are in the Bible? St Paul condemned such a theory in 1 Corinthians!!