So my advice is to learn about manuscripts.
Let us consider more mss:
Acts 8:37
Act 8:37 And Philip said, If thou believest with all thine heart, thou mayest. And he answered and said, I believe that Jesus Christ is the Son of God.
The NIV and NWT follow the same pattern:
https://www.biblegateway.com/passage/?search=Acts+8:37&version=NIV;KJV
https://www.jw.org/en/library/bible/study-bible/books/acts/8/#v44008037
The words do not occur in the following corrupted texts:
P45, P74, Aleph (Sinaiticus), A (Alexandrinus), B (Vaticanus), C, H, L, P, psi, 049, 056, 0142; MAJORITY, Vulgate-pt, pesh, harc, sa, bo, Eth
Here is the extant literature which has the text in it:
"... E
Cursives: pc (27 are cited in our other Digest)
Old Latin: ar, c, e, l, (m*), ph, r, Vulgate-pt
Syriac: Harclean**
Coptic: MAe (Middle Aegyptian)
Armenian
The verse is cited by Irenaeus (178), Tertullian (220), and Cyprian (258). ... See KJVMT p 60 for further evidence. ..." - A Closer Look: Early Manuscripts & The A.V.; by Jack Moorman, pages 113
Additionally:
"... E, 4, 36, 88, 97, 103, 104, 242, 257, 307, 322, 323, 385, 429, 453, 464, 467, 629, 630, 913, 945, 1522, 1739, 1765, 1877, 1891, others. ...
Von Soden indicates: I b1 (522, 1758), I b2 (2298).
Lectionary: 59.
Old Latin: ar, c?, e, gig, h, l, m, ph, r;
Vulgate: Clementine am-2, tol, demid
Syriac: Harclean-with asterisk;
Coptic: Middle Egyptian
Armenian, Georgian.
Irenaeus, Lyons, Latin, 178.
Tertullian, N. Africa, Latin, 220.
Cyprian, Carthage, Latin, 258.
Ambrosiaster, Latin, 384.
Pacianus, Barcelona, Latin, 392.
Ambrose, Milan, Latin, 397.
Augustine, Hippo., Latin, 430.
"Praedestinatus", Latin, 434.
Bede, England, Latin, also cites Greek mss., 735.
Theophylact, (cor.), Bulgaria, 1077. ..." - When The KJV Departs From The "Majority" Text of Hodge & Farstad, cited by the corrupt NKJV, by Jack Moorman, page 60-61.
Additionally:
"... IRENAEUS, Against Heresies (I 1:433) "the believing eunuch himself ... said, "I believe Jesus Christ to be the Son of God."
CYPRIAN, Treatises (I 5:545). "Then said Philip, If thou believest with all thine heart, thou mayest"
PONTIUS, Life of Cyprian (I 5:268), "the eunuch is described as at once baptized by Philip because he believed with his whole heart." ...
... I have found no indication in the ANPF of a pre-400 AD Father quoting the above general passage with the disputed words omitted. There were no references to verses 36 and 38 in the indices. ..." - Early Church Fathers And The Authorized Version, by Jack Moorman, page 52
Additionally:
"... Acts 8:37 is in the Byzantine Greek text used by the Orthodox Greek Churches all over the world today. Here is the Greek Orthodox Archdiocese
ἰδοὺ ὕδωρ· τί κωλύει με βαπτισθῆναι;εἶπε δὲ ὁ Φίλιππος· εἰ πιστεύεις ἐξ ὅλης τῆς καρδίας, ἔξεστιν. ἀποκριθεὶς δὲ εἶπε· πιστεύω τὸν υἱὸν τοῦ Θεοῦ εἶναι τὸν ᾿Ιησοῦν Χριστόν.
It is also in the Modern Greek Bible and in the Modern Hebrew Bible.
The whole verse is also found in Old Latin manuscripts from the textline that predates any Greek manuscripts, including the Old Latin texts of ar, c, dem, e, gig, h, l, m, ph, r, t, w. Even the notes in critical text editions tell us that this verse existed in the Old Latin copies, the Coptic Middle Egyptian version, the Ethiopic, Georgian, and Slavonic, Lamsa's 1933 translation of the Syriac Peshitta and Armenian early Bible versions. It is also found in the Vulgate Clementine.
Many church fathers who lived before anything we have in the way of Greek copies directly quote this verse, including Irenaeus 178 A.D., Tertullian 220, Cyprian died in 258, as well as Ambrosiaster 384, Ambrose 397, Augustine 430, and Venerable Bede of England in 735.
For example, Cyprian (200-258 A.D.) supports the inclusion of verse 36-37 Textus Receptus when he says, "In the Acts of the Apostles Treatise 12:3: Lo, here is water; what is there which hinders me from being baptized? Then said Phillip, If thou believest with all thine heart thou mayest." (The Treatises of Cyprian )
Irenaeus (115-202 AD), Against Heresies 3.12: "Philip declared that this was Jesus, and that the Scripture was fulfilled in Him; as did also the believing eunuch himself: and, immediately requesting to be baptized, he said, I believe Jesus Christ to be the Son of God."
Cyprian (200-258 AD), "For although in the Acts of the Apostles the eunuch is described as at once baptized by Philip, because "he believed with his whole heart," this is not a fair parallel. For he was a Jew, and as he came from the temple of the Lord he was reading the prophet Isaiah," (Cyprian)-Cyprian THE LIFE AND PASSION OF CYPRIAN, BISHOP AND MARTYR 200 - 258 paragraph 3
Augustine (354-430 AD), Sermons on Selected Lessons of the New Testament - Sermon 49: "The eunuch believed on Christ, and said when they came unto a certain water, See water, who doth hinder me to be baptized? Philip said to him, Dost thou believe on Jesus Christ? He answered, I believe that Jesus Christ is the Son of God. Immediately he went down with him into the water." ..." -
https://brandplucked.webs.com/acts8372829.htm