Making nav menu links fully customizable from CMS

I am struggling to make all nav menu links (including drop down links) customizable from the CMS. Does anyone have a way of doing it?

It is a big issue that clients are not able to add and remove links on their own.

It seems like I am not able to nest collection lists in the nav bar, and therefore I am only able to make the drop downs adjustable from the cms.

It would be great to hear if any of you have a solution for this!