Well, Giyu's prediction doesn't have many feats. He just instantly knew that Tanjirou was going to use Breath of Water technique twice, for a Breath of Water master that should be a piece of cake. He couldn't predict Tanjirou throwing an axe at him even before he was even training as Demon Hunter (He obviously dodged it though, but that's different from predicting). and Genichiro is extremely skilled and experienced in fight. If Giyu pushes him to wall, he will go Way of Tomoe and start spamming lightning that stunts opponents.
That's different. Giyuu couldn't predict that coming because of the fact that he threw him off with a strategy that would've ended in his death just to kill him. Had it not been for the fact that he took note of his missing hatchet, then he would have been dead.
Spamming lightning can be dodged or Lull can be used.
Not entirely, and shockwaves aren't very similar to lightning sent from the sky, sure, maybe Lull with deflect arrows coming at him but he will get tired after long time fighting (and Giyu can't spam Lull), Genichiro shrugs off being stabbed in neck two times in a row and through chest.
And Genichiro can massively extend the range of his sword with lightning, would be hard for Giyu to block it (pure energy tbh)