1/ origin of Arabs / Arabic according to scientists :
The origin of Arabs is still a matter of debate. Some scholars say they originated south (modern south Saudi and Yemen ) and then spread northwards However most scholars deny this and instead based on archaeological evidence propose that Arabs originated in the North (mainly syria Jordan and northern Saudi Arabia ) and then spread southwards.
2/ origin of Arabs according to Arab oral myths :
In the Arab oral legends (not based on research like point 1 ) Is that Arabs come from two different ancestors
*Qahtan from the south (south of modern day Saudi + Yemen ) And *Adnan from the north (a descendent from Ishmael the son of Abraham ) And they mixed and influenced each other creating the modern Arab people In fact until today there are tribes like the bani Yam who claim they decedent from qahtan and tribes like the bani tamim who claim they descent from Adnan . However this is not supported by any meaningful genetic evidence what is established is that the tribal people in Arabian peninsula have MORE than two haplogroups although J1 is the most common.
3/ “is it true that Arabs originate from the gulf /arabian peninsula countries ?”
Many people believe that this region (gulf/ Arabian peninsula) is the origin of Arabs :
But as we stated in point 1 that is not very likely as scholars mostly believe the origin to be Jordan and Syria In fact you had the dilmun kingdom who spoke an east semetic language (an Akkadian language ) which was more similar to Assyrian and Babylonian in what’s now Bahrain and East Saudi Arabia instead of Arabic You also had various south semetic languages in Yemen such as Himyaritic, sabaean, bathari, mehri, minaen etc
So the Arabian peninsula was home to various languages some still spoken today mainly in Oman and Yemen just like the Levant and Iraq are home to various languages throughout history.
4/ “where did Arabs settle in ancient times aka pre Islam ?”
Arabs were a heavily nomad people who settled everywhere Even before Islam , they were across the Arabian peninsula the Levant Iraq etc The idea that Arabs did not exist in the Levant and Iraq etc prior to Arab Muslim conquests is absolutely not true and honestly very stupid because Arabs were an integral part of that region in fact early Arabic used Aramaic as a script because Arabic did not develop its own script yet so Arabic most likely developed side by side to Aramaic .
Nabatean kingdom ( As we can see below it has parts of Egypt Syria Jordan Saudi )
An Arab kingdom in northern Iraq called Kingdom of Hatra/araba:
Qedrties, another Arab kingdom :
Yet another Arab kingdom which comprises southern Iraq and east Arabia :
All of these were pre Islamic. Arabs were an integral ethnic group of the Levant and Irag and parts of Egypt Since the inception of the word Arab. It is not “Islam” that introduced Arabs to those places.
5/ “who is an Arab ? “
Before Islam anyone who spoke Arabic and considered himself part of the Arab ethnic group regardless of their location in the Middle East be it modern day Levant Iraq or Saudi etc was an Arab like the Roman emperor Philip the Arab. After Islam, Egyptians North Africans the Levant etc of various ethnic groups adapted Arabic during the time of the Arab empires (rashidun +ummayd + Abbasid + Fatimid ) as Arabic was the influential language at that time like Latin in Europe and it stuck with them since with the other languages still existing The people themselves were not replaced they just adapted the Arabic language .
So for the millionth time no , people from Mecca Medina etc during the 7th century Muslim Arab conquest did not replace the various local people of different ethnic groups in Egypt North Africa and Levant Iraq etc There is a historical and genetic consensus regarding that.