Of course you can back this up with documentation of the Catholic Church Fathers correct?
"They abstain from the Eucharist and from prayer, because they confess not the Eucharist to be the flesh of our Saviour Jesus Christ, which suffered for our sins, and which the Father, of His goodness, raised up again. Those, therefore, who speak against this gift of God, incur death in the midst of their disputes. But it were better for them to treat it with respect, that they also might rise again. It is fitting, therefore, that ye should keep aloof from such persons, and not to speak of them either in private or in public, but to give heed to the prophets, and above all, to the Gospel, in which the passion [of Christ] has been revealed to us, and the resurrection has been fully proved. But avoid all divisions, as the beginning of evils."
According to Ignatius the Catholic Church believes it is truly the flesh of Christ in the Eucharist, and those who don’t are not but heretics.
Further in the next paragraph he says :
"See that ye all follow the bishop, even as Jesus Christ does the Father, and the presbytery as ye would the apostles; and reverence the deacons, as being the institution of God. Let no man do anything connected with the Church without the bishop. Let that be deemed a proper Eucharist, which is [administered] either by the bishop, or by one to whom he has entrusted it. Wherever the bishop shall appear, there let the multitude [of the people] also be; even as, wherever Jesus Christ is, there is the Catholic Church. It is not lawful without the bishop either to baptize or to celebrate a love-feast; but whatsoever he shall approve of, that is also pleasing to God, so that everything that is done may be secure and valid. "
In 1 John he speaks against the gnostics, Does he consider them part of the “universal church”? Does Peter in 2 Peter? Does Jude? Does St. Paul in various letter such as Hymaneus, Philetus, Alexander? Are they all part of this universal church in the bible?
We also find the valid bishop succession in Timothy and Acts.
Can you offer patristic evidence that anyone declared, as you just did, regarding the “universal church”
Peace and God Bless
edit: bolding for easier reading