Following his learning experience at the hands of JDS 1, I think Stipe peaked in early 2016 (or maybe 2015 with the Hunt fight) and has steadily regressed since then. I'd consider Francis the end of his peak (and part of me hesitates to include it as anything more than a last hurrah) -- and not just because he got knocked the fuck out by DC right after. He still has some gas in the tank, of course. He wouldn't have been able to make the adjustments to TKO DC in the rematch or win the rubber match if that weren't the case.
But the amount of punishment he absorbed in those three wars and worrying habits he displayed against an aged fighter in Cormier convince me that Stipe is on the decline himself. Better than the rookie who got schooled by JDS? Probably, but still not the guy who had a 6-win streak including four 1st round knockouts over a series of legends in the sport (albeit old and shot ones).
During that streak, he looked his sharpest: mixing up his wrestling and boxing when and where he needed, shifting away from his technical volume-punching style to start throwing serious heat (though he showed is still more than capable of the former when needed), solid cardio, granite chin & quick recovery from shots, and juuuust enough killer instinct now tempered with more discipline than before. He still did some really fucktarded stuff like getting clipped by Reem with his hands down and getting into unnecessary windmilling pocket exchanges with Big Frank, but other than that I definitely consider this time his peak.
But I digress. Yeah, I favor 2020 Stipe over 2014 Stipe for the most part I guess.