Peak for peak Jokic is better than Steph and Duncan right now. Duncan's peak is low relative to all-time greats based on the offensive numbers. Peak Jokic gives you elite scoring, playmaking, and rebounding on a better efficiency than Steph.
Shaq will be hard because he had three straight seasons of ridiculous playoff runs and his first title came with a hurt Kobe.
I don't know if Jokic will ever pass any of the elite two way offensive wings or centers in terms of peak. Bron, Kobe, Wilt, Kareem and MJ all have absurd peaks.