The most common mistake I see in PSs is a fear of detail. Details, examples, anecdotes....that is what makes a ps unique.
That doesn’t mean try to tell me reader your life story. It means telling the reader about a specific piece of work you enjoyed, or a specific situation you encountered..., how you approached it, what you found difficult, what surprised you, what you would do differently with the benefit of hindsight etc etc.
That is when your voice starts to come through and when your ps becomes memorable and compelling.
This is quite a useful site called Cambridge mentor, I had the same questions as you