It is called Gaia Ambition.
https://www.amazon.com/dp/B079KPTTC2
Lori Wells is an engineer living an average life in an average city. Her life is turned upside down and inside out when she discovers that her world is in danger as is the entire Galaxy from an overwhelming evil force bent on exterminating the human race. Her father's disappearance leads her and her fiance on a trip halfway across the Milky Way to discover that we are indeed not alone and that Lori will play a pivotal role in saving all of Mankind. To do so she will become a powerful force known as a Gaia, a powerful, strong and nigh invincible woman with great strength, speed, agility and power emanating from her beautiful, busty body. She will have help in the form of other Gaias who have specialized roles, but will they be enough, or is it already too late?