Proximity controls on iPhone 11 Pro Max not working correctly

How do I fix the proximity controls on my iPhone 11 Pro Max?

my iPhone is displaying a range of annoying malfunctions, which are all related to the proximity controls not working correctly (as far as I can tell).

My phone has an annoying habit of switching on speaker mode when I'm answering a call - so that when I put the phone to my ear I'm deafened by the loudspeaker function (this used to happen on my previous iPhone 8 Plus - very ****ing annoying!!!!).

Also, my iPhone responds to activiations when it's in lock screen mode and I have it in my pocket (such as altering volume levels or switching tracks while playing music, or switching on the torch function when I pull my phone out of my pocket).

I'm currently updating the iOS to 14.2, I'm hoping this will cure the problems (my phone appears to have had increasing functionality issues in the last week; hopefully an iOS update will cure it!)