Refitting Warships in Infinite Lagrange

Any Stories About Infinite Lagrange or Modern Warships?

Transmigrating into History and Secretly Developing Technology on Your Own Turf

Preferably, the protagonist works behind the scenes.

Mechanical Armor and Massive War Machines

Mecha pilots, mechanics, gunners, anything goes. Please!!!!!!

The Male Lead Has a Space Battleship from the Start

A warship upgrades and roams through space, encountering space pirates.

Recommend Some Modern Warship-Girl Novels

Stories Where the Protagonist Returns to Earth with a Fleet of Starships and Shows Off His Power

Any books where the protagonist starts out with a bunch of newly acquired stuff, returns to Earth, then shows off their high-tech weapons and gives everyone a good thrashing? Please, I'm begging you!

Original Sci-Fi Space Operas with a Three-Body Problem-Style Setting, Spanning the Entire Universe