I've had my s9+ for a year and its running smoothly and great and has never suffered any damage that I know of at all. However I started to notice that if I look at certain angles on the screen or at different lighting, there are noticeable differences in the dimness and color at different points of the lcd screen. I'm also noticing that it is taking conciderably longer to charge my phone with fast charge than it had used too along with the battery life draining within 3 to 4 hours of average use youtube, netflex ect. I dont know if this is a common problem or If I should fix it considering the fact that it is happening on its own without me even causing any physical damage to the phone or bringing it underwater.
There are several things you can do to improve the function of your phone. I will list some article for you. Please let me know if any of these are helpful.
Are you able to see the links Samsung Rei posted that are named:
Charging is also slow for me recently. I own 2 S9+ phones and my best friend has 1. We are all getting the "slow charging" message. It timed perfectly with the S10 release....strange but familiar.