Hide GD Menu

You can adjust the menus in
WP – Appearance – Menus
There you can remove individual items, or choose a different menu to display.

In the menu page you will have the option to choose which menu you are editing. Then there is a tab to select where the menu should appear.

GD doesn’t have additional menu functionality, it only interfaces with the WP Menu system so chances are that the menu is there, you just have to find it.

If you need help you can include WP Admin in a private reply and we can take a look.

I added an empty menu and that hides the default items there.
Please check.

Try this CSS in your customizer
@media (max-width: 992px)

.dt-nav-toggle {
    display: none;
}