Hi there,
Thank you for the input. The code which you used is a custom one and we can not support or maintain for the future. you used the Navigation Inline Element, that element does not have the support of the clicking on the parent menu items. Parent items will open up the sub-menus and will not redirect another page.
This element is coded that way both because of the UX and technical reasons. We understand that you see such functionality that you expect in other places, but at the moment we do not have that functionality which is on your mind.
Saying that we as support staff need to reflect our customer’s point of view to our development team. That is why we added this to our internal system:

This way your voice will be heard. In the meanwhile, if there are other requests similar to this we will include the customer voice there also.
We understand that this feature might be very desired but unfortunately at the time being we only can suggest that you add another menu from Appearance > Menus which will have the same menus of the desktop but without submenus, having all the menu items in one hierarchy will help you to have somewhat the feature you want using the Inline Navigation or the Modal Navigation elements. Again we understand that this might not be a perfect solution, and it is an alternative suggestion.
Regarding to, have only one submenu opened at a time, it seems to be a good feature. Currently, we do not have that feature but I think it will be cool if we have an option on the element that will give the user choice to choose between single or multiple submenu items opened at the same time. I also added this to our internal system for the consideration of our development team. They will decide if they will implement such a functionality or not:

Regarding the last comment, I could not reproduce the problem, actually, the menu opens up to the right for you. As the last comment is talking about another aspect of the element, I suggest that you open up a separate thread and give us detailed information and screenshots to follow up.
Thank you.