If Thanos had the stones, He would murder everyone in a fingersnap but Ant Man survived Thanos after being trapped in the quantum universe so Superman trapped in an altered dimension would do him good plus he is probably strong enough to possess the stones without dying so he could steal the stones and kill Thanos with his own fingersnap.
The DC Justice league does not waste time like captain American deciding to risk the world to save vision. Or have a civil war like Tony Stark and break up the team because they were sloppy.
The justice league took on Darkside and won. Superman would overpower Thanos and stop him from snapping. Flash is fast and would not die to some bullets like quicksilver did. Wonder woman would have been more man enough to cut off the arm of Thanos rather than to hold him down.
The DC cinematic are brutal and dark and would have save the day. Infinity war was caused because the avengers were not united.