I suppose I have unusual japanese quails then.
I keep some of mine in male-female pairs with no issues, I even had two that were really bonded and never bullied each other, sadly, the hen died in the heat.
I have a large(ish) aviary that has two males and four females in it, so far going fine. It is a fairly new setup and I'm keeping an eye, but all seems well. The males were alone together before.
I do however have some pretty aggressive females. They fight with the males often and attack some of the males that can't defend themselves as well. I had an aviary (decent size) with one male and four females. The females had been bothering the male so I decided to keep an eye on them. Like 10 minutes later I found the cock plucked and bleeding! He's my rescue quail too, so I always feel extra sorry for him since I don't know what his old life was like.
I've moved those females to a different aviary. They are the ones with the two males, so they can't gang up on the one male.
I have recently moved around all my japanese quails as their arrangements weren't working. So I find there is an important aspect to consider which is the individual birds too.