Better Durability: Superboy Prime of Thanos?
Two characters in the same weight class.
Prime tanked a universe-busting explosion after tearing off Monarch's suit. He's also flown thrown the heart of the Anti-Monitor and come out unscathed.
Thanos has tanked reality-warping while passing through dimensions, a blast from the Maker that KOed him, and taken Gungir-concentrated shots from an enraged Odin.
There are far more feats from each. Overall, who's durability is better, and why?
EDIT: Title should say "or," not "of."