Uhm yea it's not the gun, and it's not the bullet weight guys, 124 and 115gr, pretty much the same in all my guns, no difference in point of impact, 124gr maybe hits a little higher than 115gr but not enough to matter at normal pistol distances unless maybe it's for a comp. I have had literally a half dozen or more gen1 m&p's over the years, full size and compact, never had a problem with any of them, I convert them over to free state triggers or put apex kits in them, delete the mag disconnect if it has it, and install my preferred sights, but that's it, they almost always hit dead on with the rear sight centered. They are one of the best polymer striker pistols by far, and the 2.0's are even better. I had one that I used as a training/loaner/beater gun between me and my dad for 6 or 7 years that probably had 25k rds through it, without ever being really cleaned, just some ballistol or oil and a rag once in a while, maybe a boresnake once or twice in all of that, it was scratched and beat to hell, slide worn shiny in several spots, frame all dinged up and worn down in spots, it lived in the bottom of the family range bag half the time with loose brass, dirt, and whatever other crap was in there, got regularly dropped on the ground, slid on, rolled around on, covered in mud, carried on atv's, dirt bikes, backpacking, top of the slide used as a hammer, you name it, it always ran fine, accuracy never changed much, only failure it ever had was an extractor and that was from abuse of someone smacking the slide closed over cheap steel cased 9mm, only reason I don't shoot it now is because I got pheasant blood all over the grip one time and my dog got ahold of it after I had unloaded it and set it down, thinking I was gonna clean it, and he chewed the grip frame up like it was a denta bone, I tig welded the barrel to the slide, and it now hangs over my reloading bench as a nice decoration, and a great reminder of all the good times had with it, and my father.
So to summarize, no it's probably not the gun, you guys just need to learn to shoot.