I bought the game a year ago, not sure if it was released on steam yet at the time but i had purchased the game for 5 bucks, is the steam key only for those who paid 5.99? Because I cannot see the "get steamkey option when trying to download the game

Steam keys should be available for anyone that bought the game directly from itch.io at any point in the past -  but not if it was bought as part of a larger bundle.