[Django]-Django admin change-list optimizing query: select field1, field2 instead of select *

Remember that in your list_display block you can always replace x3 with x3_id to use the FK value you already have on hand and not do any extra lookup at all (ditch select_related altogether).

You could then combine that with custom functions for your list_display as outlined here to maybe replace those raw FK integers with hyperlinks to their own admin pages?