Saving Luffy is the only decent thing he did and that doesn’t help him as an antagonist. In the role of antagonist, he was sidelined for Saturn and treated as a lackey.
Kaido has more than enough feats to show he keeps up with a faster Luffy, Kuzan was humiliated in his first real outing and at best can match an already weakening Garp
It doesn’t make him Prime Garp come again,it just makes him less useless since hax doesn’t work on most top tiers
Plot wise sure, when it comes to being an antagonist or strong character? Not much