Villainess: Reloaded! Blowing Away Bad Ends with Modern Weapons (2019)

Blurb:
Astrid von Oldenburg is no ordinary four-year-old. She’s a child prodigy with a passion for military technology who now finds herself reincarnated in the world of an otome game she played during her past life. But not as the heroine! As the game’s villainess, she’s born with wealth, power, and a fearsome talent for magic. The only problem is that every route leads to her inevitable destruction. Or does it? What if averting her destruction was a simple matter of amassing enough firepower to annihilate anyone who dared even attempt to bring her down?! In a bid to resist fate, the young villainess embarks on the reproduction of all of her favorite weaponry. Whatever it takes, Astrid’s determined to blow away her bad ends with superior firepower!

Source: www.anisearch.com/manga/51387