I would suggest that your grievances are not the norm.
I have seen and used several Zastava built rifles, including the one built for Remington, the REM798.
I have seen ONE where the base mount holes weren't square to the axis of the receiver and the bases had to be modified to square.
I haven't found them to be especially accurate, say on the level of a Tikka or Sako but more than adequate for shots out past 300 yards on big game animals.
The early Zastavas had many hand made parts and were a true testament to their machinists/smiths. Sometimes the metal used for the smaller components was a bit on the soft side, especially in their adjustable triggers.
It was one of the early rifles that I saw with trigger issues. Replacing the trigger, with an after market adjustable trigger fixed it.