Doffy was probably intended to be above some Calamities. It's not clear if Oda made him weaker than he would be otherwise, but this is great Doffy hype.
Doflamingo sure used to be stronger than the commanders as we've seen with Jozu but then changed his plans for Doflamingo and made him heavily weaker in order for the weaker SNs to have a chance at beating him imo.
Wait, THAT'S WHY FUJITORA SAVED DOFFY'S ASS FROM ZORO!!
Doflamingo was no longer in a shape (his previous powerful self) in which he'd comfortably win against Zoro who was stronger than his own captain at this point.
Plus, the clear contrast between MF DD and DR DD:
MF DD: Kaido's strong ally, outperformed WB's top commanders by a huge margin and was portrayed as a top dog back then.
DR DD: showed less impressive feats than before, had to weaken Law in order to overpower him, G4th ragdolled him, was considered weak by Kaido which is in stark contrast to previous DD who should have been a "STRONG ally".