Notes are sorted in the tree in chronological order, just like the Sheets.
This order does not sort or classify your Notes other than chronologically, let alone in multiple ways.
To classify Notes, you can put the
When you put a Note into a Sheet, the Sheet is automatically represented in the Note and vice versa.
To quickly find the Note or Sheet with the Note, you can use menu items Search | Global... or Search | Sheet...
The result presents to you all the Notes in the Sheet.
From these results you can directly open the
Sheet window - double click Sheet,
Sheet panel - right click Sheet, or
Note - double click or right click Note.