https://youtu.be/OF_DdDlO2So?si=v59qXsO41hFCfxul

How to Fix Missing Appearance Menu in WordPress Admin (wpbeginner.com)

Theme twenty twenty-four has  no menu item, it uses "Navigation" instead.
Your menu comes from the Navigation block in the Site Editor. To create a new menu, follow these steps.

Visit your site’s dashboard.
Navigate to Appearance → Editor.
By default, "Design" => click "Navigation"
Note: or select the Template or Template Part you want the navigation menu to appear. 
Click the "+ Block Inserter" icon.
Use the search field in the block inserter to search for “navigation”
Click the "Navigation" block to add the block to your site.

Add menu items to "Naivation" block
Click the 3 vertical dots next to "Naivation" to brin context menu and click "Edit"
Click the "+ Block Inserter" icon to add menu items. Eg. page or url/links.
Save the changes.
Go to the page and refersh it. The change should take effect.