iPhone 7 freezing and crashing

I phone 7 plus is constantly freezing especially when i trigger it to use any hardware piece for example using the volume buttons it freezes launching the camera it freezes signing out of apple id it also freezes .now I've noticed other problems after screen replacement the loudspeaker is not working the cameras when launched we get black screen front and back and moreover the home button flex is torn but what i cant seem to understand is leaving all other things aside why would it freeze is it due to the torn home button flex cable