I don't think we should necessarily have menstrual leave. Some women have trouble-free periods, others have very heavy periods, with lots of pain, causing vomiting. Some women find hormonal contraception a godsend; others react badly to it. Some of us work in offices, where we can go to the loo whenever we want. Others have to stand in a classroom or a shop or be out on a building site or whatever. We do not all need the same solutions, because we don't all have the same experience.
What companies should have is policies around menstruation and menopause. This would mean if you have a regular pattern of sickness absence, it wouldn't vount against you if your employer uses a version of the Bradford factor, in the same way that pregnancy illness doesn't count,or illness related to a known disability. It can also cover discrimination, so you couldn't say your colleague is a hormonal liability and discount her for promotion etc on those grounds. There are various other ideas - the TUC has advice about menopause policies, as do some unions.
I think flexibility is key. Like a previous poster, I have found it easier to deal with my period working from home, at least on the first couple of heavy days. I can easily work from home in my job, though, even before lockdown. My manager is not that bothered if we finish early one day, as long as we have done 40 hours over the week. That's not the case for many roles. But lockdown has proved a lot of roles have more scope for flexibility than had been thought.
I agree that better medical acceptance of gynae issues would be a good thing for everyone, though, regardless of whether someone is emoyed or not. My employer provides private health cover, but it doesn't include menopause, normal pregnancy or menstrual issues, which are the things most women will go through at some point.
I also think that entirely normal things like periods and menopause should be less of a taboo in the workplace. Back when we worked in the office, I decided to not hide a tampon up my sleeve when I went to the loo, but just hold it normally in my hand. When I mentioned this to a younger colleague, she thought this was quite a radical move. I don't know if anyone's actually noticed, though, not even when I dropped one on the floor in front of reception (just clumsiness, not planned.) I've also told male colleagues I've got period pains when they've asked how I am, and it's the case. Mind you, what I actually wanted to say was, "all the same work as you, and period pains, too, so what are you complaining about?" But I didn't. But that is the thing, we are often performing as well as, or better than male colleagues, while having to deal with periods, however individually hassley they are, and we are meant to behave as if nothing is happening, rather than getting recognition for being even better.