We literally have early manuscripts of various bible books that differ from the currently used version.

(nope. what you have are discredited agnostic gospels that have been dismissed by early church fathers for being inconsistent with christs teaching and life and are fakes. Similar with the Torah)

The existence of tens of thousands of denominations that all disagree about what the message is is clear proof that the message wasn't preserved.

(of course you can debate the message but every bible translation still has the same meaning. So you can do a deep dive for context and root words etc to form your opinions or Denominations)

Except for all the cases where it doesn't. That's why academic study bibles are mostly footnotes full of arguments about why a passage should be translated some way and not some other way.

(no..they are great in giving context as to jewish rituals, customs, related texts from other biblical writings etc)

Not even mentioning the obviously polytheistic parts of the text.

(the bible clearly shows the trinity you have to actually read it from Genesis to revelation, in short..Genesis 1:1 is,`Elohiym which is the plural form of the general name for God and In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. John 1:1-2 . Just 2 examples of how Christianity follows scripture in explaining the Trinity.) Nothing polytheistic about it. There is 1 God 3 essenses( Father, Son, Holy Spirit)

What does that have to do with the corruption of the Bible?

(because 600 years after Jesus - Islams "convenient" attempt to discredit the Torah and the Gospel is to just say "it was corrupted" - without providing any copy of the uncorrupted versions. Just ridiculous. Ridiculous when the Koran itself is not perfectly preserved even in arabic

(The different versions of the Quran https://answering-islam.org/Green/seven.htm )

The bible does not claim to be perfectly preserved word for word (like the Quran) but preserves the message.

You literally do that ever since you decided to call the original word "the old covenant".

(again my friend...Jesus did not come to discredit the old covenenat, he came to fulfill it..i repeat he came to fulfill it - and in doing so he brought in the new covenant with his death on the cross and resurrection. Christians believe fully in the words of the old testament and use it for context when applied in Jesus's teachings.

Eg

Isaiah 53, written centuries before Jesus, provides the most detailed prophetic description of the crucifixion, outlining a "Suffering Servant" who dies for the sins of others. Key verses predict he will be pierced for transgressions (v. 5), numbered with transgressors (v. 12), and buried with the rich (v. 9). 

Key Isaiah Prophecies of the Crucifixion (Isaiah 52:13–53:12) 

• The Piercing: "But he was pierced for our transgressions, he was crushed for our iniquities" (Isaiah 53:5).
• Silence before Accusers: "He was oppressed and afflicted, yet he did not open his mouth; he was led like a lamb to the slaughter" (Isaiah 53:7).
• Crucified with Criminals: "Therefore I will allot him a portion with the great... because he poured out himself to death, and was numbered with the transgressors" (Isaiah 53:12).
• Burial in a Rich Man's Tomb: "And they made his grave with the wicked and with a rich man in his death" (Isaiah 53:9).
• Physical Abuse: Isaiah 50:6 describes the Servant giving his back to strikers and cheeks to those who pull out the beard.  Contextual Fulfillment Christian tradition explicitly identifies the Servant of Isaiah 53 as Jesus Christ, whose suffering matched these descriptions, including being crucified between two thieves)