Phone speaker turns on randomly during a call

Hello,

During a call while I have the phone at my face on my ear, the screen randomly goes on and the speaker button is being pressed by my cheek.

Is there any option, that the phone screen is OFF by default during a call (not that I have to turn it off with the side button manually every time which is impossible to do every phone call) and if i want to use the screen then i press the side button to turn it on ??

or any other option that resets the issues with the sensor?

I really need your help because this is really dangerous to my eardrum (the speaker is damaging it while turning on unexpectedly with full loudness)

Thanks in advance,

Brane