Of course women are going to be less happy now that they have more responsibilities and more stress. Before women's rights, a lot of women could live in blissful ignorance about the world. (this was obviously not true about women who had to work back then too while they were getting paid less than men and there was 0 protection against sexual harassment in the workplace)

Everyone knows that with more responsibility comes more stress. That's why a lot of people say that childhood and the teenage years are the best years of your life, since you barely have real responsibilities. That is not an excuse to attack women's rights. If there existed someone who was happier as a slave because they had a slice of bread to eat and a bed to sleep in instead of having to be independent and look for a job, does that mean that slavery is a good way to live your life?

Being submissive leaves women vulnerable to all sorts of abuse, that's why a lot of women nowadays hate the idea and want to be independent. Being less happy as a result of more responsibility is not an excuse to deny women that right.