''Hi,''
''T''o prove whether it is a software problem or a hardware problem you may have to perform a [https://help.kogan.com/hc/en-us/articles/360013594533-How-To-Factory-Reset-a-Xiaomi-Pocophone-F1|hard reset]
''***Be aware*** that a ***hard reset will erase all your data and downloaded apps***. It will restore the phone to its factory default condition.''
''Backup the phone to the cloud or a computer before performing the reset. Also if there is a Google account tied to the phone, you will need to know the account name and password to access the phone once the reset has been performed due to the FRP lock (factory reset protection) being enabled by the reset.''
If you’ve already done a hard reset (you didn’t mention if you did) then it is a hardware problem. So dropping the phone may have contributed to the problem. Here’s the ifixit [[Topic:Pocophone F1]] guide that will help you to open the phone and check for any obvious problems e.g. loose connections or cracks in the systemboard etc.