Hi @Lupirite
I would have suggested to not open up the sealed casing as this will have voided your Samsung Manufacturers Warranty.
I appreciate you've cleaned it but your not in a dust free environment so dust will possibly re-enter the phone and further damage could have occurred during the process of unsealing the phone etc.
Although water damage isn't covered by the warranty a Samsung Experience Store or Samsung Service Centre would still have helped albeit with a fee attached but they probably will not now.
Water ingress can cause oxidation to the internals corroding vital parts of the internals and affects the motherboard.
It can also depend on what water it was and what was in it. Fluoride / minerals etc.
I would have suggested to just leave it turned off in a warm dry area like an airing cupboard for a few weeks.
The rice method has it's uses but sadly isn't always successful 😔
If your still determined to see if you can get the phone working then I'd suggest to get a qualified mobile phone engineer to take a look to run through some diagnostics with it.
Ic can depend on the age of the phone to it's current value and how much time and expense you want to invest in the phone.
May I add > Look to insurance via Household Contents Insurance or some Bank Accounts provide cover as a perk of the account or if the phone was supplied via a network as part of a contract look to see if your covered by them or if your due an early upgrade.
News-rules-faqs/community-policy-on-dangerous-diy-unorthodox-repair-advice.
However you proceed I wish you all the best. 
