What is the question? In detail?
Online MLS is dead on SFOS.
Online MLS as provided by Jolla (why is it still in Settings if they will never require an API key from Mozilla? Or will it come soon ™? Silence!) does not work!
MLS offline tool can calculate rough position from cell towers. (provided from community on openrepos as well from Jolla in store).
But this does NOT help speed up GPS fix (edit: on XA2, just provides a faster rough positioning). In general rough positioning should speed up GPS fix locating satellites faster.
Maybe this link helps you?