As someone who comes from a gun family, I can tell you that most floating barrel guns aren’t nearly as accurate as fixed barrel guns, by nature. And that huge silencer likely does nothing to alter that, instead making your shots even slightly less accurate. A shorter silencer would probably help, but that’s debatable. My dad can zero almost anything, but sometimes you can only do so much.
That said... at that distance, you should be able to keep your shot groupings at center mass. So, that is a little odd. Did you try shooting without the suppressor on a different target? It could be possible it was mounted incorrectly or worse, manufactured as such.
I doubt wear and tear has too much to do with it. Assuming it gets cleaned. I shot a Thompson about ten years ago and it was the most rented firearm at the range, yet I couldn’t tell for a second that it was in any kind of disrepair.