iPhone black screen

My iPhone is showing a very dark blue screen, almost black. I’ve tried force restarting multiple times, but nothing changed. I can tell the force restart is successful because after about 10 seconds, the screen goes completely black (probably showing the Apple logo), then turns back to a very dark blue (likely when the phone is starting up). I read that I should connect it to my computer via USB, but I’ve never done that before. When I tried, the iPhone wasn’t recognized. However, when I plug it into a charger, it makes the charging sound, so I know it’s working, but the display stays black. What should I do?