But he didn't destroy the universe with the IG. U stated he destroyed the universe twice, which he did not do. He destroyed the universe once with the HotI. But then again, Reed Richards destroyed the universe with the Ultimate Nullifer (including Eternity) and recreated it without Abraxas as a threat. Morg, who's not the brightest bulb, managed to scheme his way to the Ultimate Nullifier also. Are you saying that Morg & Reed Richards > Eternity, Infinity, Etc? The Living Tribunal trumps the IG. Regardless of how anyone feels about TOAA, his position is canon. Also remember that the Infinity Gauntlet had no effect on Maelstrom when Maelstrom confronted Thanos with the IG (confirmed as canon too by Marvel's Official Handbook)
The Infinity Gauntlet is über powerful but there are some artifacts and characters more powerful than it, or at the very least unaffected by its effects.