There are many "MMA/boxing analysts", like that ThePainGain dude, or that MMA Guru or wtv (this dude looks kinda disturbed tho) that sees the Jon Jones vs Stipe fight as underwhelming as it looked slow to them...
Nevermind the fact that if anything, Stipe proved that in that last fight that was meaningful to him, he was considerably better than Gane, Volkov, etc... Jon Jones vs Gane looked like a mismatch... Jon Jones vs Stipe looked like a fight in which someone could give Jon Jones some trouble, but only to an extent, mid difficulty.
Stipe was likely in a considerably better shape than vs Ngannou. He got older, but getting older doesn't always makes one worse. Sometimes taking a break off the game, finding a fight that they want (in case, since the start, Stipe said he'd go back to HW no matter whether JJ appeared there, but that with JJ there, that's the opponent that to him, made it perfect). He stated with that poker face in some podcasts that to him, fighting Jon Jones is even above the belt itself, that having his comeback be a super fight vs Jon Jones is great because he wanted to fight JJ above all). It could be seen after the JJ vs Gane fight, in which Stipe was soon interviewed, that he looked motivated and excited, he told about how it's such a big deal having Jon Jones as the opponent and that he was already preparing to push his training...
... When asked about Tom, Stipe sounded dismissive and even said "if I have to fight him, ok, we'll figure him out of JJ and I'll fight him, but my focus is on Jon Jones totally, that's what matters to me". That fight was already anticipated with both JJ and Stipe getting a win over DC. Stipe is often cited as not only the best HW, but the most complete one and the one with the highest fighting IQ... He likely sees the fighting IQ of Jon Jones, he knows JJ is the biggest name one can fight against in MMA, ever... He seemed to me to be having his motivation waning a little with time... He beat DC twice, then faced Ngannou after winning once, and the payment was just not good for those HWs... For Stipe, a reigning champion, the biggest name there alongside Ngannou, it might have been frustrating to be fighting constantly and earning so below what his abilities as a fighter would make it more than valid to earn way more... He's got kids, he's risking his healthy, and getting paid what he should of be paid more fairly would be a bigger motivator... As well as the fact he never adopted a trash talk posture because he is not that way, he isn't gonna fake something besides what he considers enough as a fighter... So despite being the best heavyweight, he was fighting monsters with a rewards far from what he deserved. The JJ fight brought the biggest fight money he had ever had, and JJ is arguably a name that excited him more. Ngannou maybe in the first fight, but fighting with him again, already not being satisfied with the ways of UFC but being mostly silent, likely didn't bring in him the motivation — which the JJ fight, with ppl doubting he should even be there, gave him plenty — Stipe said the fact people were already taking his loss for granted only fueled him even more, as he likes shutting people up.
That fight was likely against Miocic in which he had to offer as his best as a fighter.... Having already gained experience from many fights and having that motivation for one last time in such a significant event.
Jon Jones might be better now than he was in the past... He had an easier time vs Stipe than vs Cormier despite the fact this Stipe was likely better than the Cormier Jon Jones faced... And likely the best opponent he has already faced, the Stipe that, with the motivation for one last big show, is likely better than Ngannou and all heavyweights...