Sorry to hear that you spent the extra money for a gun which is not working out for you! I have had one or two guns in the past with features (particularly triggers) that absolutely did not work for me. They got traded off quickly. I'm one of those strange people who doesn't believe in putting extra money into buying custom pars for a gun which should function well from the factory.
I know nothing at all about any of the S&W Performance Center models. However, with some professional shooter exceptions, most guns are more accurate than the shooter.
This may not apply to you, but my experience working with women shooters is that when they learn the proper grip, stance, SMOOTH trigger pull, and how to get and hold a perfect sight picture - accuracy is there. (I'm not talking about bullseye shooting which is a different thing, using different guns.)
I have enjoyed my Shield EZ - standard model, no external safety lever. I'm not as accurate as I was 10 years ago, with my arms and hands being a tad shaky now in my old age, but the gun itself is dead on. It's not the smoothest or lightest trigger of any gun I own, but I shoot the same size groups with most all of my guns and the EZ has been a fun one for me to shoot.