Hi,
There is a lot of change that comes when Odoo was upgraded from version 14 to 16. Currently, in the case of the backend, we are using OWL (Odoo Web Library). If you want to import "Documents Inspector" using the updated OWL JavaScript syntax, you can use the following code snippets:

/** @odoo-module */
import { DocumentsInspector } from "@documents/views/inspector/documents_inspector";


For importing DocumentsKanbanController:

/** @odoo-module */
import { DocumentsKanbanController } from "@documents/views/kanban/documents_kanban_controller";

Hope it helps