And yet the original subject of this thread was to show that the Trinity text was added centuries after Matthew wrote his Gospel. It originally did not contain the words "baptizing them in the name of the Father and of the Son and of the Holy Spirit".
That claim, even if it is true, does not rule out the beliefs of the whole Church.
From the OP:
"Fraternal Visitor, in The Christadelphian Monatshefte, 1924, page 148, states, "Codex B. (Vaticanus) would be the best of all existing MSS if it were completely preserved, less damaged, (less) corrected, more easily legible, and not altered by a later hand in more than two thousand places. Eusebius, therefore, is not without grounds for accusing the adherents of Athanasius and of the newly-arisen doctrine of the Trinity of falsifying the Bible more than once."
Christadelphianism (another made-in-America cult) denies the divinity of Christ, and misquotes Eusebius by omission, so your credibility is in the toilet from the start. Athanasius proved the whole Church had always been trinitarian, and that is why Arius lost out. The tradition of Arianism was non-existent.
Baptists at Nicea and other myths
“the first and only begotten of God which was before every creature and creation visible and invisible, the commander-in-chief of the rational and immortal host of heaven, the messenger of the great counsel, the executor of the Father's unspoken will, the creator, with the Father, of all things, the second cause of the universe after the Father, the true and only-begotten Son of God, the Lord and God and King of all created things, the one who has received dominion and power, with divinity itself, and with might and honor from the Father; as it is said in regard to him in the mystical passages of Scripture which speak of his divinity: "In the beginning was the Word, and the Word was with God, and the Word was God." [John 1:1] "All things were made by him; and without him was not anything made." [John 1:3]”
― Eusebius of Caesarea,
Eusebius of Caesarea: Ecclesiastical History
It should be noted that Eusebius is not a Church Father, but a historian.
ORIGEN (c. 185 - 254 A.D.) (not a Church Father)
TERTULLIAN (c. 155 - 250 A.D.) (not a Church Father)
NOVATIAN (c. 235 A.D.) (not a Church Father)
St. Ignatius of Antioch (c. 110 A.D.)
Aristides of Athens (c. 140 A.D.)
St. Justin the Martyr (c. 100 - 165 A.D.)
St. Melito of Sardes (c. 177 A.D.)
Athenagoras of Athens (c. 180 A.D.)
St. Theophilus of Antioch (c. 181 A.D.)
St. Irenaeus of Lyons (c. 140 - 202 A.D.)
St. Hippolytus of Rome (c. 200 A.D.)
St. Clement of Alexandria (c. 150 - 216 A.D.)
St. Cyprian of Carthage (c. 250 A.D.)
quotes are here. None of these men denied the Trinity.