If you have got your phone wet and can no longer turn it on using the power button, but it shows as charging when you connect it to a charger; you might be able to ‘wake it up’ by doing the following.
1 – Hold down Volume Up and Volume Down
2 – Plug in the charger.
With a bit of luck, you’ll see a warning about loading a custom OS.
Press the Volume Down option to ‘restart phone’
You should now have a phone that’s started up.
If your touch screen is also dead, you can probably attach a standard USB Mouse (might require a USB to USB-C adapter) and operate the phone as needed to get your stuff off it.
You might be able to make use of this phone as a video surveillance camera, etc.