Playing a Doujin game as mercenary mecha pilot across multiverse

Y/N just your regular high school student. He is not hardcore gamer but he plays regularly and is not picky about what game he played. During his school long holidays his friend give him a mysterious package containing the game he never heard of.The moment he logs into the game, it might lead him to an interesting life or maybe not. Note: Inspired from Ace Combat in Multiverse and several other fanfic such as gate jietai war thunder and muv luv gamer. Please don't expect a good story. I Write it just for fun and not serious. Very low motivation as my previous work is abandoned as I lack the idea and interest (I'm writing this on impulse). Also English is not my first language so expect a lot of spelling and grammar mistakes