But still collapsible is not giving a good experience for author they are unable to understand which panel is under which collapsible unless they expand and navigate. Is there a way i can read the values of panel or subpanel nodes stored underneath the /content and populate the jcr:title field of Container at run time or any alternate solution to make authoring experience good with collapsible.
True.. With these many levels of nesting, the collapsible layout with expand the selected and collapse the others and make it difficult for authors to view even in full dialog mode.
This looks like something that is probably used for a menu. If it's going to be authored only at one place, can you consider implementing this using container components? Each multifield section being a container component with ability to author desired properties at that level.
Other option is exploring granite/ui/components/coral/foundation/well in place of/ combination of granite/ui/components/foundation/layouts/collapsible
You should consider using container and section component implementation. Basically the container component will have responsive grid inside which you will configure section (child) component. The authoring will be much easy and the container component can be reused for multiple such requirements.