Battery Drains fast 55% in 10 hours without using it.

its more than likely board damage. My guess would be a filter or three is corroded but it could possibly be the charging IC. Really the only way to tell is to throw the board under a scope, clean any corrosion you find, replace any bad parts you find, then try again. If its still doing it, its probably the IC. But that's not even 100%.

I'm of the mindset that water damage is basically a death sentence for a phone. Even if you spend hours cleaning and fixing it, there is no sure way to get all the damage and its almost certain that other issues will pop up. Most people repair them to the point they can recover their data, then move on.