You could add an additional popup type to create overlay navigation menus like mega menus, fullsize mobile menues etc. The special thing about it: The trigger button of the popup (e.g. burger menu button) turns into the close button of the popup.
There is no good plugin for creating menus in Divi yet. Tested several plugins, they don’t offer the right features.
Or you maybe want to create a seperate Divi Ultimate Menu plugin that offers even more features to replace Divis outdated standard menu ;)
I’m sure you could do that perfectly with your knowledge.