I want to get rid of the fake lock screen!

[Android Central Question]

Hi guys.
I got my new phone just yesterday. A Samsung M20.
It was working just fine until evening when I got a additional lock screen from which I have to swipe and then enter my password. I googles this issue a lot and all of them suggested me to delete the culprit add. But here is the catch, I didn't download anything apart from what's app and my airtel app. If anyone could help , I would be grateful.

 

[B. Diddy]

Welcome to Android Central! Does this extra lockscreen have ads, or include some other bogus functionality like "RAM cleaning"?