Hi, I am sorry you are experiencing these issues with your Note 20 having a black screen. If your phone or tablet displays only a blank screen, there are a few things you can check to determine the cause of the problem. For example, your device's battery might be dead, or maybe it just needs to be reset. You can try these troubleshooting steps here: https://www.samsung.com/us/support/troubleshooting/TSG01001470/
Please inform me if this helps your situation.