Not necessarily. If the pool of talent is exactly the same(let's say 1000 women and 1000 men) and your interviewing process is perfect at determining engineer quality, but you are hiring 80 women and 20 men, then you'll hire the top 2% of men and the top 8% of women. Again, just assuming that the talent is exactly the same, the women you've hired will still be worse.

In reality, the pool of female talent is very shallow. Again assuming the talent levels are exactly the same, there's just not enough highly-skilled women to go around, e.g. if you're trying to hire the top 1% of engineers, and you have a pool of 1 million men and 100,000 women, then you're looking at 10000 men and 1000 women as your potential hires. If the top 1000 women are already taken, then you're forced to relax your interview requirements for women. In fact, if the pool is completely free for your usage, but you're looking to hire 10000 men and 10000 women, you'll be hiring the top 1% of male talent and down to the top 10% of female talent, which should lead to a difference in output.

This doesn't mean that "sexism" isn't real or that it's not a problem women face in the workplace. The question however, is how to measure the effectiveness of "anti-sexism" practices employed, if you cannot measure the effect of "sexism" itself, as it is entangled with all the other, confounding factors. You can't optimize performance if you can't measure the effects your solutions have on it.