Delulu is just a spin on another word, rizz is the same
Random affixes are common enough that it’s normal no matter how weird any given one is
But skibidi is literally a filler nonsense word. It’s like if we just put random scatman words and beatboxing noises into the dictionary. It’s babble, which would mean it has a place in the dictionary as an example of babble or gibberish.
But it doesn’t actually /mean/ anything by it self. So it’s just weird to see it getting added as a “word”.