Are those who create satirical videos mocking the name "Mustafa," which is prevalent in Egypt and symbolizes the diligent student, sinful, and do these videos fall under the ruling of backbiting?

Mentioning diligence in study is not considered backbiting, because it is neither a flaw nor disliked. Backbiting is mentioning a person with a disliked defect that is present in them. If it is not present in them, then it is a slander (buhtan). Backbiting only occurs with specific identification, or when the listeners know who the speaker is talking about.