The issue I have with that is that there is no actual anti-feat though for Full Power Erza to not be High 6-C in 100 Year Quest, she overpowered and destroyed Deus Sema, she did that at her Full Power in X792, it's very clear she got stronger from the beginning of the Alvarez Arc to the end, everyone did, for the rest of the Alvarez arc after her battle with Irene, she's crippled and weakened for the rest of the arc, in 100 Year Quest, she's only been fighting with her Base Armors and only ever loses when in those Armors, and she's only gotten serious twice, once against Mercphobia, who scales faaaaaarrrr above Dragon Irene and Laxus, there's no feat of her losing to someone weaker than Irene when she's using her full power at all past the point she destroyed Deus Sema
Once again, now that I have realized it as we are now, the burden of proof is to prove she isn't that strong with her Full Power at this point and there isn't any, she's only lost to people who scale far above her previous peak and even someone stronger than Irene
I promise you guys, I'm not trying to wank, I'm simply looking to apply logic to the current scaling at this point and I cannot think of a single reason why she shouldn't scale to High 6-C in her full power, I mean it would only scale to her and Laxus anyways