More of the same visual signifies more power. New visual suggests new power.
What kind of logic is that?? It’s still obviously force lighting, and given that Palpatine was rejuvenated by the Dyad, the red lightning is apart of that. It’s just more powerful force lightning. What makes it red? The force! It’s Star Wars! It’s really not hard at all. I sound like a broken record but you’re overthinking this way too much.