The Firefox 85 version is scheduled to include an option that would allow users to remove the "Other Bookmarks" button, but this is not available yet for Firefox 84.x users.

How to Delete Multiple Bookmarks at Once in the Bookmarks Menu of Mozilla Firefox. Mozilla Firefox allows you to store Web pages you visit often as bookmarks.

If you have previously added some buttons to your Firefox menu, you can just as easily remove them to provide more room for other features.

On the Bookmarks Toolbar, the Live Bookmarks folder for a website is marked with a standard Firefox folder icon marked with an orange feed icon. To delete this folder, right-click it and select ...