It should be 7 men 3 women, on average
No, it should not. That’s just ridiculous. You don’t fix unequality by maintaining it just because that’s what you’re always known. You want to keep the privileges you have now while denying improving the situation of others, because you think losing your unfair advantage over others becomes unfair to you, that’s nonsense.
Hiring 50/50 is not discriminating against you just because you were at 70 before. You don’t get to decide that half the female population of the planet shouldn’t be allowed to work - because that’s what your 70/30 is, if the 70 is most of the male population (let’s imagine a >90% employment rate), then the 30 is around half of the female population, you’re saying the other half will never be allowed to work. You’re assuming they can keep being SAHM or whatever else.
The thing is that the 70% of workers being men shouldn’t mean there are less men if it becomes 50%. Men aren’t losing their jobs. It means there are more workers, including the same number of men, and more women. This isn’t supposed to be a zero sum game when population grows.
Everyone getting the same chance means 50/50 hiring because believe it or not, women do want to work in all fieds; the current 70/30 soon goes down to 50/50 from there. And yes, men do want to work in healthcare and child care and education, surprise. Why do you need to make sure they can’t? Because that is in fact the same process that happens, one side is actively shunned from some jobs and the other side gets shunned all the same, even though there are people on both sides who do want to work in both types of jobs. The reality that you pretend doesn’t exist is that there are 10 women who want to be an engineer at the beginning of their education and they get stomped down to 1 until she gets passed over for some 10 men who at first wanted to work in healthcare but were bullied into engineering. This 1 woman to 10 men scenario is your own creation.
It takes actual work of being unfair to maintain the imbalance you benefit from. Man you don’t even understand the math of your own argument, maybe the women who get hired over you actually are more skilled.