It is not possible by default; you have to use an additional menu module and replace it. This requires the use of a custom header with a unique position for the new menu module and logo.
I did it a few times in the past, so it's possible after all, but extra skills are needed. Customization task.
In Helix Ultimate, the navigation menu (Main Menu) works with the keyboard (web accessibility), but in the old Helix3 templates, it doesn't. Using a different menu module might help with that. However, the menu is one issue; the wrong color contrast is another.