How to correctly fix water damaged?

so the story goes like this

the phone was droped in the toilet for a moment and picked back up and put for about 6 hours in rice then not turning on.

so ten i got the phone the phone was cracked and water were almost every where (a bit here a bit there) and there was already a bit of corrosion mainly on the top mother bored so i took a tooth brash and some 97% alcohol and rubed it all out put everything together and only blinking led and nothing.

did some more research and decided to take apart everything submerge it in alcohol for a day and then scarab all the corrosion out (did it) and nothing same thing

fast foreword to now i got a new screen and replaced it and now the led is on like its charging and nothing else works

any advice ?