When selecting a sort order in list designer:
Release : 20.4
In DX UIM 20.4 CU7 and later, the sort order is only respected within List Designer itself - meaning that if you save a List in the Designer, when you reload that same list in the Designer, the saved sort order will be respected. However, this doesn't translate to the List Viewer - when viewing it in the Viewer, for now it will still sort by the primary column (usually hostname).
In DX UIM 23.4.2, there is a bug - sort order is not respected/saved in Designer or Viewer.
In DX UIM 23.4.3 and later, this is resolved, and the sort order is maintained in both Designer and Viewer, so a list with a sort order saved in List Designer will be loaded with the same sort order in List Viewer.