Haki and Devil Fruits would bypass it. Magic isn't the thing that bypass the invun, it's Supernatural things in general.
The skill gap shouldn't be too vast considering Luffy's own solid feats and scaling.
Saber doesn't have temporal based Precognition, her Instinct is outright stated to be within the realms of Precognition and even then there are several types of Precognition, to which Luffy has multiple of. Luffy can also just evolve into developing Future Sight mid battle due to Haki's growth.
Also Luffy can drastically become faster and stronger as time goes on, his RE has let him cover gaps of thousands of times in the past. He has experience in dealing with opponents with Precognition, has durability negation in the form of Red Hawk, massive speed amps with Gear 2nd, has wide ass AoE with Gear3rd and has crazy good RE and RPL.
I don't see how Saber is taking this.