Here it says that ๅ (boku) used by women has a feeling of gender neutrality in #Japanese
https://www.youtube.com/watch?v=MNR0egvK_oQ&t=296s
But it also says that there are two pitch accents for ๅ, and grown-ups tend to use the raising / flat version.
When watching the next episode of the Tengoku Daimakyou #anime, I'll try to notice to which version is used by female characters.