I think Oliveira because he has many ways to finish. His staight right has been hurting fools, his bjj from the bottom & in scrambles would be far & away the most dangerous that Khabib has seen, his clinch wrestling is extremely underrated, & his clinch striking is lethal.
He also has been throwing a lot of wild switch-knees/jumping front kicks/up-elbows the last few fights.
I think if anyone is going to beat Khabib it won't be by decision. Charles 3.0 is as dangerous as anyone in mma right now, from everywhere.