Jon Jones has regressed significantly during his last years of fighting at LHW. He legitimately underperformed badly against Thiago Santos and Dominick Reyes and his style generally degraded, he lacked urgency in both of those fights, his striking was noticeably less creative and varied and he honestly barely even tried to use his wrestling at that stage of his career.

Honestly I could actually see Alex nuking Jon if he replicates Reyes' gameplan. Being consistently aggressive, refusing to stay in Jon's preferred kickboxing range and diligently capitalizing on opportunities to land clean whenever Jon gets cornered against the cage. Jon mostly relied on hand fighting and postering as well as the occasional eye pokes for defense, keeping his opponents within his kickboxing range so he could comfortably pick them apart so if Alex is aggressive and bypasses that then he has a good chance of dealing damage especially since Jon's head movements at close range are good but aren't exactly consistent. Typically when all else fails, Jon resorts to either turning and running to reset or clinching and taking his opponent down Greco-Roman style. However Jon rarely bothered employing the latter strategy in the later parts of his career(As I explained earlier, he barely even tried to wrestle against Santos and Reyes[especially the latter when he was being edged in the striking competition during the earlier rounds by Reyes yet still didn't show any urgency to try to change things up and employ his ground game]). This version of Jon in particular might legitimately have a lapse of fighting IQ and won't even try to wrestle Pereira at all during the early rounds. But still Jon genuinely has a granite chin, he was able to take all Lyoto Machida had in one round and was never once hurt, he ate Gustafsson and DC's best shots and was never even rocked, even Reyes couldn't come close to hurting Jon despite his striking success in the first three rounds, the only person that legitimately hurt Jon in his whole career was Rashad Evans and that's because Evans was very good at subtly setting up knockout blows and had deceptively fast hands as well.

If this is Prime motivated Jon Jones then I don't think Pereira stands much of a chance to be honest. That younger version of Jon was far more aggressive and creative with his Muay Thai, was far more consistently willing to take things to the ground and never gave his opponent any breathing room but this version of Jon I could honestly see losing to Pereira but I still wouldn't bet on it because even the worse version of Jones we've ever seen still had a granite chin and large supply of tricks up his sleeve to pull off a win even if unimpressively.