If someone is found guilty and sentenced, but it is found that there were discovery violations pre-trial, what happens?

Specifically in New Mexico criminal cases.

Say you're put in prison, but the prosecution played dirty in the discovery/pre-trial phase. Does any evidence that comes out after the trial matter? As far as I've seen, post verdict the rules are a bit more stringent on evidence that comes up: it has to be reasonably assumed that the verdict may have been different if the evidence was present, not merely impeaching or contradictory evidence, etc.

But even if the evidence was "merely impeaching or contradictory" evidence, if its not disclosed to defense pre/during trial before the verdict, what happens? Not that the evidence was discovered after the verdict, but that it was there, prosecution had access to it pre/during trial, but it wasn't disclosed, and a guilty verdict was established?

Also, say there is potential evidence that the prosecution/investigators stall accepting until it is too late for it to be properly examined/designated as an exhibit for the defense to use in trial, does that count as a discovery violation?