Going by your revised question:
>“how did Jesus become God? ”, if he wasn’t born to a virgin.
Being born of a virgin is not a requirement for godhood in any religion and was/is not a requirement for the Jewish Messiah either. It's also extremely debatable whether Jesus was perceived as God during his lifetime.
The Virgin Birth is unknown by Paul or by the authors of Mark and John or by any other NT author besides Matthew and Luke. Marcion didn't seem to know that story either. It seems to be a fairly late development, probably invented by Matthew.
The reason why Matthew invented the Virgin Birth story is unknown. It was not necessary in order to fulfill any Messianic expectations or prophecies.The prophecy cited by Matthew himself - Isiah 7:14, the famous "immanuel" passage, is not about the Messiah and does not say "virgin" in the Hebrew (the Greel LXX mistranslates the Hebrew word almah - "young woman" as Greek parthenos, "virgin. The Hebrew word for "virgin" would be bethulah)
In fact, it's problematic for the Messiah to be born of a virgin because, definitionally, the Messiah has to be a direct descendant of David through the father. It has to be "Seed of David." The mother's lineage doesn't count. Adoption doesn't count. Deuteronomic law did not even have a concept of legal adoption.
So why did Matthew want Jesus to be born of a virgin? That's all conjecture but some scholars - in particular I would cite R. Joseph Hoffmann and Jane Schaberg that conjecture that Matthew may have been concerned about accusations that Jesus was illegitimate or had questionable paternity. That is an accusation found in the Talmud that seems to be pretty old. In particular, I'd recommend Schaberg's book, The Illegitimacy of Jesus: A Feminist Theological Interpretation of the Infancy Narratives. Her car got firebombed in the 80's after she published this book).
Schaberg is not saying these accusations were necessarily true, but that they were believed, and so Matthew and Luke were responding to that.
There are at least some reasons to think it could have been true. One of those reasons is Jesus being referred to as the "son of Mary," when men were not usually called the son of their mothers unless their fathers were unknown. I mean, it's all circumstantial but none of it's impossible and it has explanatory power.
Specifically the allegation was that Mary was raped by a Roman soldier named Pantera. This is in the Talmud and also addressed by Origen responding to Celsus. The grave marker of a 1st Century Roman soldier by that name has actually been found in Germany.
More from James Tabor's blog on that:
https://jamestabor.com/the-jesus-son-of-panthera-traditions/