I honestly believe Jones got shook by Ngannou. I think Ngannou would have sent his head into a shadow realm if they fought. I don't think it's a coincidence that Jones came back right after Ngannou left either.
Jones hasn't arguably looked good since he popped for PED. I mean he destroyed GUS, but Gus had a bigger decline than most since.
Jones is probably the greatest fighter in the history of UFC or MMA if you ignore PED. I don't though and I can't.
If Gane didn't look so god awful when Ngannou wrestled him, nor the fact he doesn't train outside training camp which makes no sense since this guy doesn't have martial arts background, I mean he got into Muay thai late too, I would be more confident in predicting this fight, but oh boy he really looked like he didn't know what he was doing. And Jones is arguably best MMA wrestler of all time.
I still favour Gane though. Gane actually didn't look that bad grappling in his ufc run, though obviously he hasn't fought a strong wrestler yet. Also, no one knows what Jones is going to look like with added weight and wrestling someone who is as long, big and athletic as Gane. I think Jones hasn't looked good for a long time, coming off a long lay off, with a big unknown in this fight which will determine the fight: How good is Gane's wrestling when he's expecting the takedowns, and how good is Jone's wrestling/cardio now at heavyweight against a gifted heavyweight like Gane and how will he look with added weight? No one can be sure of the answer.
But with what we have, I think I'd pick Gane by UD or late finish. I don't think Jones will be what he once was.