My two cents.
Oliveira is almost identically dangerous in striking and on the ground, he likes to put pressure. He has over 1000+ techniques how to sub. Makhachev works as number 2, likes to counter. Yes he get punched rarely, but if he get punched well, he looses (his only loss in UFC for example). Compared to Oliveira, who recovers heavy punches on the back. Makhachev technique - go single or double leg, ground and pound or try to kimura or triangle. Oliveira has a lot of more techniques. However, I think Makhachev has more stamina. But question, will it help against Muay Thai aggression and black belt in BJJ ? Olivera is so expert in BJJ, that he uses only hands and legs; he does not even use help of his head to control his opponent. Everyone knows that Makhachev is an expert in wrestling, like Khabib. But check Khabib vs RDA fight. Khabib did not do much against RDA on the ground, and as soon as RDA legs were close to Khabibs head, Khabib steps back and continue fight in stance. Makhachev is not Khabib, he did not put pressure all the fight.
Compare both fighters opponents. Olivera has finished every single top5 fighter (except Makhachev). Makhachevs best opponent was top10 Tsarukyan, who he won by decision. I'd bet on Olivera.
I think Oliveira is going to win, by TKO or sub.
Even if I do think that Charles Oliviera does win by TKO I just cannot think Islam Makhachev is being beaten by Oliviera by submission.
Someone mentioned above, It's difficult to believe Charles Olivera is so proficient at the ground game when he has tapped out 8 times in his career?
If it is a ground-heavy fight, it is going to be a win for Islam Makhachev. There is also a possibility that he will want to take the fight to the ground as well. However, the problem is I don't think his takedown is as effective and unexpected as Khabib's. There is a possibility that Charles Oliviera will try to read Makhachev and expect the takedown, and will attempt to defend it. The problem is if Makhachev can make Oliviera carry his(makhachev's) weight when the fight is on the ground Oliviera will get tired quickly. So I think Oliviera will try to keep fighting and standing up.
Odd's are also supporting Islam Makhachev