If there’s a whole surah in Quran on women, why isn’t there a surah for men too?
And if Allah doesn’t have a gender why is he referred to "He" in the Quran?

1) The rulings in the Quran are generally for men and women unless specifically pointed out. Since there are some laws pertaining to women only there is a sura in the name of women.

2) God is referred to as He in the Quran not because God has a gender but because of the Arabic language which has a natural masculine gender. Some languages like French and Arabic have nouns as naturally masculine. English doesn’t have that natural masculine because it has It- as opposed to He. Whereas the Quran used the word هو which means He for gender or It for an object that is gender less (as it is used for God)