Its a catch all diagnosis for underdeveloped executive functioning. The biology you are talking about is a description of a neurological state.

It does not mean it cannot be developed. It is underdeveloped due to prefrontal cortical issues pertaining to early life experiences which shaped the personality. This is absolutely something thay can be changed.

Https://www.apa.org/monitor/2014/04/adhd#:~:text=In%20addition%2C%20treating%20the%20kid,catchall%20for%20lots%20of%20things.