Are you taking DCs complete MMA career or just UFC career?
DC was past his prime and still won two belts.
The fact that Jon Jones, the GOAT, and Stipe, the HW GOAT, were his only losses past his prime shows how elite he was.
DC didn't win a vacant HW title.
DC has more wins, against better competition, against more varied styles, and as an undersized fighter.
DC is a better and more complete fighter than Poatan IMO. As much as I like Alex, if he fought during that era, I struggle seeing him get into the Top 10 let alone a TS.
If he fought during Jon and DCs era he doesn't touch a belt. If even past prime DC was fighting in the current LHW division, he feasts on everyone and racks up multi defenses.
Of course, Poatan can pass him up, he still has the, but as of now, I don't think he's better or greater than DC.