remove Uncategorized from Menu and footer

You can control this with an SEO plugin such as Yoast or Rank Math, for example.

Alternatively, you can prevent the visibility of this via PHP code. You can find more information here: https://wpassist.me/remove-unwanted-uncategorized-links-from-your-posts/

You would need to ask Divi support whether the commercial theme/plugin you are using offers options for this: https://divi.help/ – questions about commercial products are not permitted here in the forum.