A genuine question , why does islam allow slavery , incest and objectification of women?

Recently ive lost faith in islam but my mother insists that i should study my deen properly , that turned out to be even more problematic because now im stuck in a dilemma of pleasing my mother or refuting whats wrong

1st slavery.

Theres no need to explain that slavery definitely existed during the time of the prophet

But then why didnt he condemn it , he is supposed to be the most noble man yet he himself had slaves and there is a certain hadees where the prophet is preeching the ways to not hit a women

Source: sahih Al-Bukhari 5204

In this he says that a women should not be beaten like a slave but he never restricts hitting a women or a slave

Just that women should be less abused then the slave

I wont discuss the next part it get a bit problematic

2nd Incest

I dont think ill need reference or explanation for this one its pretty common knowledge but ill explain the places i find it problematic

Adam and his spouse are supposed to be father and daughter by technicality and they still decide to mate and thats acceptable since they werent really scientists

But i think its still a scientific blunder because how did they inbreed for so many generations and still get fertile off springs?

And Muhammad himself married his first cousin

3rd objectification of women

Multiple verse come to mind but i only remember one so ill take about that

Islam allows polygamy and some people like to argue it was for the time of the prophet and his people but doesnt allsh say that the quran is eternal if its eternal then that means its still right and if you think its wrong then how is it eternal