There is a huge difference between the methods on which the Quran was gathered and how the four gosples were gathered , on one hand the Quran' writting began in the time of the prophet peace and blessings be upon him by his companions and then gathered into one single piece during the time of Abu Bakr may god be pleased with him a year after the death of the prophet peace be upon him by Zaid ibn thabit and finally put into multiple copies during the time of Uthman may god be pleased with him.
The four gosples on the other hand we do not know who the writers are, we have fragments and papyrus here and there but there writers are unknown. To make matters worse, these fragments (which are only small sections of the gospels) are copies of a line of copies (of which their authors are unknown) ending to a speculated missing original text. The writers wrote portions or fragments of the gospels within scattered areas of southern Europe and North Africa and the people started hearing them and transmitting them orally throughout the Roman empire. The oldest complete bible is the codex sinaticus written about 350 AD !!!

Now I will present a detailed description of the gathering and writting of the Quran and the four gospels:

First the Quran :

a. The Quran was written first during the time of the prophets :
Narrated Qatada:
Anas said, "The Qur'an was collected in the lifetime of the Prophet (ﷺ) by four (men), all of whom were from the Ansar: Ubai, Mu`adh bin Jabal, Abu Zaid and Zaid bin Thabit." I asked Anas, "Who is Abu Zaid?" He said, "One of my uncles."
Saheeh Albukhari 3810

b.Then pilled up during the time of Abu bakr ( A year after the prophet) by Zaid himself :
Narrated Zaid bin Thabit:
Abu Bakr As-Siddiq sent for me when the people! of Yamama had been killed (i.e., a number of the Prophet's Companions who fought against Musailama). (I went to him) and found `Umar bin Al- Khattab sitting with him. Abu Bakr then said (to me), "`Umar has come to me and said: "Casualties were heavy among the Qurra' of the! Qur'an (i.e. those who knew the Qur'an by heart) on the day of the Battle of Yalmama, and I am afraid that more heavy casualties may take place among the Qurra' on other battlefields, whereby a large part of the Qur'an may be lost. Therefore I suggest, you (Abu Bakr) order that the Qur'an be collected." I said to `Umar, "How can you do something which Allah's Apostle did not do?" `Umar said, "By Allah, that is a good project. "`Umar kept on urging me to accept his proposal till Allah opened my chest for it and I began to realize the good in the idea which `Umar had realized." Then Abu Bakr said (to me). 'You are a wise young man and we do not have any suspicion about you, and you used to write the Divine Inspiration for Allah's Messenger (ﷺ). So you should search for (the fragmentary scripts of) the Qur'an and collect it in one book)." By Allah If they had ordered me to shift one of the mountains, it would not have been heavier for me than this ordering me to collect the Qur'an.... Then the complete manuscripts (copy) of the Qur'an remained with Abu Bakr till he died, then with `Umar till the end of his life, and then with Hafsa, the daughter of `Umar.
Saheeh Albukhari 4986

c. The same copy was used by Uthman to be copied in multiple copies and distributed to the islamic states :
Narrated Anas bin Malik:
Hudhaifa bin Al-Yaman came to `Uthman at the time when the people of Sham and the people of Iraq were Waging war to conquer Arminya and Adharbijan. Hudhaifa was afraid of their (the people of Sham and Iraq) differences in the recitation of the Qur'an, so he said to `Uthman, "O chief of the Believers! Save this nation before they differ about the Book (Qur'an) as Jews and the Christians did before." So `Uthman sent a message to Hafsa saying, "Send us the manuscripts of the Qur'an so that we may compile the Qur'anic materials in perfect copies and return the manuscripts to you." Hafsa sent it to `Uthman. `Uthman then ordered Zaid bin Thabit, `Abdullah bin AzZubair, Sa`id bin Al-As and `AbdurRahman bin Harith bin Hisham to rewrite the manuscripts in perfect copies..... They did so, and when they had written many copies, `Uthman returned the original manuscripts to Hafsa. `Uthman sent to every Muslim province one copy of what they had copied, and ordered that all the other Qur'anic materials, whether written in fragmentary manuscripts or whole copies, be burnt.
Saheeh Al bukhary 4987

The same copy that was written at the time of Abu bakr was not burnt

d.The reaction of the companions to uthman making multiple copies of the original was that they were pleased:
Zaid is reported to have said, "I saw the companions of Muhammad (going about) saying, "By Allah, Uthman has done well! By Allah, Uthman has done well!" [Nisaburi]

Ibn Abi Dawud records Musab ibn Sad ibn Abi Waqqas to have testified: "I saw the people assemble in large number at Uthman's burning of the proscribed copies; not a one spoke out against him." Ali commented, "If I were in command in place of Uthman, I would have done the same." [Zarkashi]

Second :The Four gospels :

The gospel of Mark :
the oldest thing of the gospel of mark is a papyrus called p45 dated around the mid third century (It is a copy of a line of copies) Thats it!!!! No proof that Mark wrote and the writer of the copy is unknown!!!
The original missing mark is thought to be written in 40-60 AD

The gospel of John :

:The oldest manuscript of the gospel of john is the papyrus p52 dating to the first half of the second century and again it is a copy within a line of copies with an unknown writer
The original missing John is thought to be written around 90-110 AD

The gospel of Matthew :
written by someone with a jewish background copying from mark (not Matthew as the author ) the earliest manuscript of it is a papyrus called p64 containing some bits of matthew 3, 5 and 26 written by an unknown person in the end of the second century as copy from another copy!!!!
The original missing matthew is thought to be written around 80 -90 AD

The gospel of Luke:
The oldest manuscript containing some of Luke is a papayrus called papyrus 75 dated 175-225 AD by an unknown writer copying from and unknown copy transmitted from a line of supposed copies of unknown writers!!!

Both the unknown writers of the original missing gospels of Luke and Matthew are thought to have copied theirs from the original missing Mark Thus these three gospels (Mark, Matthew and Luke) are called the synoptic gospels

This is how The Quran was perfectly preserved with their known writers from the time of the prophet peace and blessings be upon him, unlike the four gospels for which christians can't even prove that Mark , Matthew, Luke and John actually wrote the gospels or who wrote those existing fragments and their copies or how was it transmitted to the anonymous writers of the existing fragments!!!