While playing games blue line appear at bottom of the screen. What it means?

In minimal usage m30s is heating atleast 45 to 46 degree. Is it normal at summer season?

Heat a lot while during few minutes of video call. And fps fluctuates all time while playing games firstly no lag but after few minutes of gameplay phone starts heating and performance becomes down.and during daily usage minor lags identify by me.

What is FACM in android?

Samsung m30s lag a lot while playing high graphics games. Itnna lag pehle nhi hota ths