Is it possible to extract the internal memory of the phone and read it

Have you looked into the water damage? There are basic steps you can do to see without opening the device. I have had some people who had water damage devices but when inspecting water barely goes into the device, which is something I find interesting with the newer samsungs.

Basic Inspection.

• Sim Tray- pop it open and remove the tray, look around for a White or Red marker (its a sticker inside the phone.) if you see Red, then water went inside the phone. If it’s white or white with purple marks, most likely minimal to no water went inside the phone.
• Inspect the charging port - this one may be a bit more difficult if you don’t have a magnifying glass or sharp eyes. Get a light and inspect for Greenish debris/residue. If you see this, you can simply clean it with 99% alcohol, tooth brush, cloth, and a hair dryer on standby. Apple to the brush but not to the point where it’s dripping. just a small amount. Hold the device upright and brush it (literally like brushing teeth). Pat it dry and apply some heat to dry the alcohol. Inspect and see if the residue is not gone and the gold contacts are visible and clean. After drying the alcohol let it sit for 5-10 mins. Do a test charge and see if it will charge.

This should at least help connect to the computer, then you can use samsung smart switch application to transfer everything to the computer.

I hope this helps!