First I’d ask, are you a power lifter or bodybuilder?
I k ow mentally benching heavy weights is great but from an ascetics standpoint it doesn’t really matter.
Second and I admittedly didn’t read all the posts, you need to break down the movement and see where you are failing. Top range, bottom, middle? Work those positions and train out of them. If you are stuck in the bottom so dead stop bench from pins. Middle position, try block training. Too do more lockouts. Over load some negative work also. 100%+ 1 rm with a spotter perform some real slow negatives