Women mansplain too. I’ve seen it happen a multitude of times.
I agree, there are just annoying people who stupidly try to explain things you know more of.

However, I have to say, there were times when I was mansplained, and it was clearly because of my gender, it happens.

One time about 20 years ago, I was working at a restaurant as a dishwasher when I was asked to train a new employee. I did.
About three months after his training finished, he started lecturing me on how to do my job correctly. Of all the wtf. He would seriously pull me aside and lecture me on how to do my job, after I trained him. It got so annoying I spoke to management about it.
They literally giggled (all guys) and explained that I was a very cute girl and the guy clearly had a crush on me. They told me it was a compliment and I should be flattered. He was trying to “show off” to me by acting like he knew more than he did and wanted by to “show off” they explained.
For the love of hell this was so stupid and insulting. And it was clearly happening because I dare be a woman who this idiot find attractive.

Another time when I was working as a math tutor, I had a student who couldn’t handle the fact I was a female who knew more than him (I literally was working as a tutor) and he would only accept help from me after he talked about my appearance and how ironic It was I was a math tutor. He never did this to my male colleague (but made jokes about how silly it was I was the math tutor, my colleague was an English tutor). Ar one point I would teach math to my male colleague (who was ab English tutor) just so he could teach the sexist guy the math, which then the guy would listen to and not attempts to argue okay stupid explaining games with. My attempts to help him were also only successful when I let him act like he knew more than me and allowed him to teach me something he felt he knew. He also made a habit of making of false claims about science I never said, and reporting that I was wrong.

This was rather rare, for every jerk like this I encountered, there would be 12 decent men who were normal same individuals. But there were these jerks, and my male colleagues had no problems with.

There are also as you explained female mansplainers. Hell, one time my Mom called me up and tried to wrongfully explain the laws in my own state (she lives in a different state). She is a momsplainer- which is a common thing among moms lol.
But i gotta say, there is a special bread of mansplainers, who act a bit different if you’re a man vs a woman.