Yes, finally, after ten years, I have found out how to save the result list from SmartPlaylist as a normal (non-smart) playlist in Music. There, you can rename it, play it, reorder titles, edit it, sync it, delete it.
You will get this feature with v13.2, in the list view options (upper right corner).
Each time you tap "Save as Music playlist" a new playlist is created with the (same) name (e.g.) "SmartPlaylist X - Name of your list" and description "Created: date/time".
