Reborn in 1978: The Fake Heiress Is Actually a Real Commander

[A doomed second female lead, a fake heiress and a real heiress, a heroine who's a top student, a leading figure in military industry, and clear-eyed about life.] Zhan Yan, a top weapons and electromechanical expert from Huaguo, is reborn in 1978 as the doomed fake heiress, the second female lead in a short period drama. No one suspects a thing. They still think she's the naive, willful little rabbit they can bully and humiliate. Her fiance wants to enjoy the sight of both her and his mistress in bed. Her adoptive parents want to use her to get close to a high-ranking official's son. The real heiress wants to step over her corpse on her way to the top. But she's the one who proves most capable. She decisively leaves home and breaks off her engagement, then crushes the competition in the fields of machinery and weapons, where only men used to hold sway. She keeps shattering everyone's expectations and gets rich overnight, step by step becoming a true member of the elite. The high-ranking official's son who dumped her, thinking she was too obedient and worthless, starts regretting it and comes back to pursue her. She also learns that the fake heiress's tragic death in her previous life was a conspiracy jointly orchestrated by her family and fiance. In that case, she'll catch them in the act, dump and punish the scumbag, and cut ties with her family to take revenge, all at once... P.S. This story is set in a completely fictional history and is not based on any real-life people. The plot is entirely fictional. Please don't nitpick or make comparisons.