I'm more talking about the additional 70,000+ years of unknown exposure he's had, especially seeing that it showed him being far stronger than he was before. That plus additional powers he gained across that period of time is substantial. Post-Flashpoint got those powers over a period of a few hours of solar absorption at best, not completely out of the question for a guy travelling the universe and fighting "evil gods" to gain that much energy as well.
Plus, i think backscaling is fine as long it line up with continuity, and not having any real feats doesn't automatically mean he's weaker. Besides, SP1M is considered by WoG to still be the
strongest metahuman ever so the text is still considered true.