Suddenly lost my Recent apps icon from my Navigation pannel in M31.How can i solve this. Pls Help me to correct this issue

I am facing issue with proximity sensor in Samsung galaxy m31. Whenever I call someone the screen goes off (black). And blinking of Screen randomly. Pls help me with some solution. Thanks

Yesterday while charging Samsung M31 for  upto min. 3 hours it got from 29% to 43%. Even in fast charging this issue has been occurred two times yet. Before this, the device was slow charging like around 9-10% in an hour. But now it is getting worse....