I'd say that for the most part we have changed the social system to be more fair.

Yes, we have, but clearly not enough. Example: A huge part of the overall wage gap can be attributed to the fact that most workplaces simply aren't flexible enough to accommodate women who become pregnant and have to take care of a young child for a few years. Hence there is currently a huge opportunity cost between career success and having a family. So, the mass of women who choose their career end up driving down the fertility rate, and the other mass of women who do choose to have a few children end up driving up the gender wage gap at the same time.

The obvious solution to both these problems is to get the state to extensively subsidize childcare and pay for it with increased taxes, like they do in France. But of course in America they're idiotically resistant to anything that makes sense.

Gendered oppression is often not about sexism at all; a lot of the time there's just some shitty economic or political policy behind it.

If women tend not to be as interested in working 60 hours a week as men, why should we need them to? How is that oppressing their full agency?

Because it denies them wealth and promotions, putting them in an inferior economic and social position that leaves them weak when it comes to representing their collective interests (like including women's reproductive health in company healthcare packages, or making sure they aren't sexually harassed) and defending their collective rights (perhaps if we had a few more female billionaires to lobby Congress, they wouldn't have dismantled abortion access across the South).

Again, if we were talking about two rival nations, nobody would bat an eye at the suggestion that an equal balance of power ought to be maintained between them to deter any threat of invasion. But when it comes to social classes at odds within those nations, suddenly the more powerful party objects to any such notion that everyone ought to have sufficient leverage to protect themselves against exploitation.