Islam truly is Arabization, all Muslims either willingly or unknowingly to some extent embrace Arab culture upon adoption of Islam as a faith and way of life or those brought up into it from birth. Like you said the Quran was written in Classicsl Arabic and memorized in Classical Arabic, and can’t be translated for some reason which forces all Muslims to learn Arabic in one way or another, even those Muslims who don’t speak Arabic or don’t come from any Semitic cultures such as Indians, Pakistanis, Africans, Europeans, and so forth. Its the reason most of the Middle East has become Arabic speaking and countries such as Iran and Turkey are very Arabized in culture despite being non Arabs and Iran’s rich pre-Islamic history. It’s also considered to follow the Sunnah to grow a beard and any cutting or trimming of the beard is considered a violation of the Sunnah of Mohammed, the fact that you have to follow Mohammed a seventh century Arab pagan in everything you do in life including going to the bathroom and acting like him in all forms of daily life is both ridiculous and pure Arabism.
Christianity however in my view is adaptable to every single culture and assimilated into every culture it came into contact with and overcame the Judaization of the faith as we saw in Acts of the Apostles. Although Jesus was an Israelite and Judean, all Christians including myself keep our own individual identities and cultures, Europeans stay Europeans, Africans stay Africans, Chinese remain Chinese, and so forth. As Apostle Paul once said:
There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus.
Galatians 3:28
Narrated Wathilah bin Al-Asqa': that the Messenger of Allah (ﷺ) said: “Indeed Allah has chosen Isma'il from the children of Ibrahim, and He chose Banu Kinanah from the children of Isma'il, and He chose the Quraish from Banu Kinanah, and He chose Banu Hashim from Quraish, and He chose me from Banu Hashim.”
Jami` at-Tirmidhi 6:46:3605
"I have heard the Apostle say: '
Whoever wants to see Satan should look at Nabtal.' He was a sturdy black man with long flowing hair, inflamed eyes, and dark ruddy cheeks. He used to come and talk with the Prophet and listen to him. He would carry what he had said to the hypocrites. Nabtal said, 'Muhammad is all ears. If anyone tells him something he believes it.' Allah sent down concerning him: 'To those who annoy the Prophet and say that he is all ears, say, 'Good ears for you.' For those who annoy the Apostle there is a painful punishment."
Ibn Ishaq: 243
Narrated 'Abdullah bin 'Umar: concerning the dream of the Prophet in Medina: The Prophet said, “I saw (in a dream) a black woman with unkempt hair going out of Medina and settling at Mahai'a. I interpreted that as (a symbol of) the epidemic of Medina being transferred to Mahai'a, namely, Al-Juhfa.”
Sahih Bukhari 9:87:162
“Islamic” Noah:
“Ham [Africans] begat all those who are black and curly-haired, while Japheth [Turks] begat all those who are full-faced with small eyes, and Shem [Arabs] begat everyone who is handsome of face with beautiful hair. Noah prayed that the hair of Ham's descendants would not grow beyond their ears, and that whenever his descendants met Shem's, the latter would enslave them.”
Al-Tabari, Vol. 2, p. 21, p. 21
Historical Islamic scholars and jurists:
Ibn Khaldun (1332–1406) was, among other things, an Islamic jurist, Islamic lawyer, Islamic scholar, Islamic theologian, and hafiz
“Therefore, the Negro nation are, as a rule, submissive to slavery, because [Negroes] have little [that is essentially] human and have attributes that are quite similar to those of dumb animals, as we have stated.”
Ibn Khaldun, Muqaddimah, 14th century
Al Jahiz (781–869), was a famous Muslim scholar
“Like the crow among mankind are the Zanj [African Blacks] for they are the worst of men and the most vicious of creatures in character and temperament”
Jahiz, Kitab al-Hayawan, vol. 2
Ibn Sina or Avicenna (980-1037), was, among other things, a Hafiz, Islamic psychologist, Islamic scholar, and Islamic theologian
“[Blacks are] people who are by their very nature slaves.”
Quoted in “Blasphemy Before God: The Darkness of Racism In Muslim Culture” by Adam Misbah aI-Haqq
Nasir
Al Din Al Tusi (1201-1274), was a Shia Muslim Scholar and Grand Ayatollah
“If (all types of men) are taken, from the first, and one placed after another, like the Negro from Zanzibar, in the Southern-most countries, the Negro does not differ from an animal in anything except the fact that his hands have been lifted from the earth -in no other peculiarity or property - except for what God wished. Many have seen that the ape is more capable of being trained than the Negro, and more intelligent.”
Nasir al-Din al-Tusi, Tasawwurat (Rawdat al-taslim)
So yes Islam does promote Arabs over non Arabs and does Arabize its adherents.