I bought my Samsung Galaxy S21 Ultra 5G three weeks ago and have been enjoying it until today. I installed the latest software update, and this morning noticed that when playing videos on specific apps such as Twitter, Discord and TikTok; rows and lines of green, black and sometimes yellow pixels just flickering.
I got in touch with Samsung's support team on Twitter, who advised to clear cache via recovery mode. To my surprise my phone wouldn't enter recovery mode either no matter how many times I followed the steps of holding down the power and volume up button.
Eventually I was advised to just factory reset my phone as a last resort. I did this a few hours ago, on top of a poor job at syncing my files, the problem did not get solved. The flickering on videos has stopped on Twitter, for now, but is still on apps like Tiktok, and now on Discord (which it wasn't on before the factory resetting).
I spent a lot of my savings on this phone and have no idea what else I can do. I've attached images of the pixelation issue below.