Hi YongOk Kim,
Recently I used the mendix tree view widget:
https://marketplace.mendix.com/link/component/112707
Here we can find mpk with some examples:
https://github.com/mendixlabs/widget-test-projects/blob/master/projects/treeview/TreeView.mpk
https://github.com/mendixlabs/widget-test-projects#tree-view
I used the MultilevelTreeView.
It gives us the possibility to have more than 3 levels using the same entity and to create that levels manually or arrange a system to do automatically.
Please let me know if you need further help and if this information was useful
Perhaps what you’re looking for is this widget https://marketplace.mendix.com/link/component/38862