Since the itemLookup as the selectedKeys works with index and is not able to search the tree by a key value, which in my opinion is really a must-have feature for the tree.

It would be by far easier if we could have a method findParentsByKey and findParentItemsByKey and define a key and values and get the full results.

Like for example

findParentsByKey(id,  123)  - this could return an array of objects of the key/values of the parents of the node with id: 123.

findParentItemsByKey(id,  123) - return only the parent nodes (only those with children), an array of objects with the key/values of each parent item.