I have recently come across another person who identifies with this term and we have made an updated flag for it. For those who haven't seen the original post, Girlneoboyfluix is used to describe alignment with bigenderfluidity while also identifying as Girlfluix and Neoboyflux. The original coining post can be found here - https://gender.fandom.com/f/p/4400000000000118793
The colours of this updates flag represent the two genders together, with pink taken from Girlfluix to represent femininity, the purple and blue are taken from one of the neoboy flags, white is for transition and green is to represent being a boy in a less binary way.