Iphone 12 pro max display flickering

Hi. I bought an iPhone 12 pro max 3 days ago when I want to watch a video clip at night in a very dark room without lights the background starts flickering . Actually the video itself is okay but the black areas up and down of the video are flickering . The pixels are turning gray /green then black and this circle is continuing every 3/4 seconds. I just want to know that this is a software problem or a hardware problem because there is no apple store in my country. Also there is a video on YouTube that displays pure black hd when I the video starts the flickering starts too continuously.