Hi Anna
sorry to hear your phone is still not waiking up.
well you already followed the gude: ✏ How to handle water damage @Meaghan posted.
and you tried cleaning the display assembly connector as posted by @urs_lesse.
and after that charged the phone like @urs_lesse posted.
after all this staps its still very difficult for my only reading the information on this form to find what part of the phone ore maybe parts, are damaged.
dit you check the water damage markers as described in form wiki about watter damage, can you share if they were discolored?
my you can take the phone to your local repair shop they can do a diagnosis.
from this point wat i can see it can still be each part of the phone.
im thinking about, drained battery, display assembly or main board.
maybe you can order multiple parts if the shop agree with sending it back after you tried that part.
i can only guess if it was waterdamage, or maybe rapid temperature chang and freezing of the phone. or the schok from dropping on the ground.
maybe someone else on this form have a better plan?