This isSadly a bad representation of what would actually will happen.
Not the worst simply surface level, seen some chinese or korean ones....well they were either just switched genders (lazy) or tried to make reversal world but many things were of our standard world that don't make any sense in the reverse world.
Why a bad representation? Males are 16.5% of the world population i.e. 1:5.
Even today in Europe for example average metric is like that - for every 105 males there 100 females. By age 40 trend reverses.
Even with such small difference women are more arrogant and demanding (as portrayed in this manga but IRL women i think are less extreme).
My point is European, US and some Asian women are already starting to act like in this manga. What does it mean?
It means that in 1:5 ratio there would be really crazy stuff happening.
Harems would be not an option but a male obligation in order to pacify unrest among women.
Strong lesbian movement (bi). (among women there are more gay/bi people)
Also women on average are far more willing to share a man than man willing to share a woman.
Even today i hear sentiments from women that they are willing to share a high earning man, men on the other hand would rather be poor guys with no woman than be one of the boyfriends(husbands) for a rich lady. (Not every guy but vast majority)
So this manga isn't bad per se but it is out of touch with many points here that it is seems completely artificial to me, like almost no brain power was involved in studying the causation of such phenomena. + Out all Japanese male population we once again get the one who is basically a incel. With his game or rather lack of it his chances of striking a girl are almost zero in our world instead teaching young Japanese males the correct behaviour for mating strategy they creating a world that is made for them.
And even a world made for them is too complicated for them to hook up with someone.
Not expecting much but at least some logic. What i wrote took me minutes to think up though i knew some studies and statistics before hand but they also do not require a lot of time to read or to understand.This isWendy'sMangaDex. Don't go in expecting solid worldbuilding/internal logic from an isekai manga. You'll just be disappointed.
I don't know about you guys, but i think these girls will end up k*lling each other, my bet is actually on the college friend going against crazy office lady