Congratulations on your new bundle of joy
The only Gen4 experience that I have is my model 26 and it has been 100% now after ~2,000 rounds through it. As far as the availability of 9mm ammo is concerned, here in NC I have seen the same thing. Both now and in the past. A few years ago when there was such a drought in ammunition, I would ask the man or woman behind the counter if they had any .38 or 9mm and the answer was always the same. They would step aside and show me the almost empty shelves. They had rifle ammo, they had a good selection of .22 LR and a few boxes of .40 S&W. One time they had a few boxes of .40 S&W and a few boxes of .357 Sig. They sold out of the Sig ammo, but they always had .40. Which showed me that the 9mm was still in big demand. Enjoy your new addition to the family.