Moisture detected warning hasn't gone away after days of trying to fix

Yes, replace the port. I myself haven't figured out why this happens, but I see it at least a few times a month with a wide range of galaxy devices. Just make sure you order the port that corresponds with your model. If you order the wrong one, it will cause issues such as a "no sim" message. You can find the model number of your device by going into settings, scrolling down to about phone, and somewhere in there it'll give you the exact model number which is the letters "SM-" then usually 4 numbers and one or sometimes even two letters.

I assume this will work for your phone as well...

Worked on a Samsung SM-T510 tablet, came in with moisture warning symbol and wouldn't charge,. So i replaced the port with the correct replacement and still the warning appeared. Now here's the weird part.. when the tablet is in download mode or in factory reset mode the battery will charge with no issues, power on the device to home screen, plug in charger with no issues.. this moisture symbol warning only appears when the battery has been depleted. So the trick is not to let the battery die, but if you do, you will have to charge in download mode for 20mins or so then power on device and plug back in to to full charge.