Contention: A Litrpg Apocalypse (Welcome to the Multiverse) by Sean Oswald ,

With less than a month left to prepare the Earth for what is about to happen, Silas must pull out all the stops to save as many people as possible.

Of course is one system wasn't bad enough, Earth has been declared a contested world and now it isn't just the Earth competing any longer but at least two systems trying to gain control of the Earth.