Not being able to depress the grip safety is the shooters way they grip the gun, they are not gripping it correctly, my advice is to order up a NDZ grip safety in their preferred color and when the grip safety is replaced with the NDZ grip safety take the spring and go to a good hardware store and buy a weaker spring that is close to the original size and shape as the original, install that spring in there and should be good to go, I own both a 9 EZ and a Equalizer and both have a NDZ grip safety, if you shoot a hundred rounds in one day the stock grip safety will cause the web of your thumb to hurt a bit but with the NDZ grip safety it depresses down to be flat and your hand won’t hurt when shooting a hundred rounds, both of my guns have the stock spring but I replaced the grip safety's and triggers with the flat style Galloway trigger before I ever fired them, it transforms them into a easier to shoot more accurate handgun, after 50 years of being a mechanic, my hands are crippled up and full of arthritis and my thumbs don’t hardly work, the 9 EZ and Equalizer are the only handguns I can operate properly, I have shot the 9 EZ for years and have run at least 5000 rounds thru it without a single problem so it’s my EDC, the Equalizer is my home defense handgun with the Viridian green dot scope and Viridian green laser/1000 lumen light, I have ran close to 2000 rounds through it without a hiccup, I have been shooting handguns for over 60 years and these 2 handguns are the easiest to shoot in most accurate guns I’ve ever owned besides my Colt trooper mark lll, shooting handguns is about the only fun thing I can do anymore with four cervical vertebrae and three lumbar vertebrae fused together and the arthritis that goes along with it and not being able to lift 10 pounds without hurting for days.
