my friend you can believe what you want; but one thing please keep in mind the biggest sin in monotheistic religion is associating partners with God or in its divinity, similarly attributing towards God which it did not say. So we should be very very careful in this regard.

Every Prophets over centuries is consistently asking people to come toward that same one God ; but ( according to Christians believe) some how with Jesus every thing changed , God become three in one; has to come to the earth; needed to die on cross for salvation and so on. rational question is why nature of God suddenly changed?

you said "This is one of the lies Muslim try to pass off" Muslim theology is very simple and is consistent with history. God is one who send Prophets and with Muhammad PBUH came the last Prophet - believing in these two tenant make one a Muslim ; salvation is not given but has to be earned through deeds and its only some thing God can decide ( there is no guarantee) ;

Another Muslims has ton of Problems ; and one of them is they dont read and research religious text there is a very few minute percentage who will read bible and comment on it ; most of them have not even read Quran in a language that they can understand

Irony in your argument is you said Mark, Matthews, wrote the bible and they are not anonymous; but than you said its the Injeel that God reveal; if human are writing the bible than how come its the same text. Another one raised in an article below which I wrote

"Also, all four books have anonymous writers, so it's possible they were delivered in an oral form to a community of people, and then they wrote it later.

It's also an understanding that Mark and Luke were not written by anyone who knew Jesus personally. The gospel of Luke even starts out with an explanation that he is collecting accounts of what happened from others and that the author himself is not an eyewitness.

Most of the material in Mark is copied in Matthew and Luke, but if Mark met Jesus and Matthew and Luke did not why Matthwes is word-to-word copying them?"

Please read (below article) if you get a chance; for any rational person its hard to swallow Christianity with all these contradictions and ambiguities; hence we are noticing lot of Christians moving toward Atheism/Spirituality.

https://medium.com/@mfakhar2000/jesus-was-none-but-a-prophet-b26aea21247e