There is a little water damage in my phone , but the SIM card is fine

You put your phone in the water on purpose? Is it not working at all? Apple will not replace your phone based on their claims of water resistance. So, that’s not an option. If anything, I would open the phone and clean it good with alcohol. If you have access to a shop that has an ultrasonic cleaner, I would get them to remove the board and clean it. Hopefully there is just light corrosion causing whatever issues you are having with the phone that will be remedied by an ultrasonic cleaning.