Battleships, Go Mad!

Everyone Awakens a Starship, and the Protagonist Commands an Aircraft Carrier Fleet

Looking for books like Mecha Girl Era: All My Mecha Girls Are World-Class (Code Name: Kindling).

System + Interstellar War + Battleship Building + Civilization + Space + Sci-Fi + Mecha

Warship Commanders, System, Interstellar Warfare, and Infinite-Turn Stories

Could any fellow readers recommend something?

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!

Interstellar Novels with Warships, Fleets, and a System

Space travel and battles between space fleets, without mechs, and with a System eventually.