Very close fight Miocic was just starting to come into his own and JDS was at the end of his rope as an elite HW. Prime JDS has a good chance against DC I just worry that what happened in the 2nd and 3rd Cain fights could happen there.
Dos Santos definitely deserves credit for it, but I think that, age aside, Stipe wasn't in his prime yet. In fact, i'd argue that despite being 38, he's still at the tail-end of his prime now. He's continued to show technical improvements in every fight since, especially since the Nagnnou fight onward. He was using stepping knees, front kicks, an accurate jab to the head and body, effective feints in this past fight. He's become more accurate, has a better shot selection and has developed a decent fight IQ which I don't remember his possessing earlier in his career. I swear, I saw him use a D'mato shift when he dropped DC which you don't see used too often in mma. He has plenty of flaws, too. His defense is suspect, but it improved since that loss. He can pull counter like he did repeatedly against Nagnnou (obviously a very crude brawler, but still). He shifted his headslot to the left to land those left hooks to the body and avoid DC from using hand control to set up his punches. His offensive wrestling has gotten better too since that loss, starting with the Hunt fight and then incorporating slipping punches to create takedown attempts. I'm not sure that Stipe would beat Dos Santos if they were both in their primes when they fought because Dos Santos was a shell by their second fight after the Cain mauling. And Dos Santos was a beast of a man and had very effective mma boxing when he was at his best. But, still, i'd probably pick Stipe in a hypothetical prime head-to-head fight. Just my opinion, though.
The best question is between Stipe 2014 and Stipe 2019 ! Problem with Stipe in 2018 was he fought Ngannou 5 month before ! His chin wasn't recovered and we can't really compared with other version of Stipe ! For me, Stipe was in his prime in 2019 and DC was very close to win with a good fight IQ ! He won 3 round and fight toe to toe with Stipe and take body shot, i think i could won a little decision even if he lost the 2 last round ! Stipe in 2019 was at his best : best chin ever, best endurance ever, best skills ever, best fight IQ ever, very good punching power, it was his absolute peak ! I think this version of stipe win a slight decision over prime JDS !