Researchers recently announced that they were capable of using Starlink to get the position of a receiver, instead of GPS. Without any support from Starlink, they received signals from multiple Starlink satellites and using NORAD data to obtain the position of the satellites, they computed the position of a ground antenna within 10m.
This is not as good as GPS but it is an impressive achievement for a starting point. The concept is to use the new constellations as SOP or Signals Of Opportunity: this does not require support from the operators and is based on the great number of satellites and LEO orbit (instead of 24 satellites for GPS at 20000km of altitude). Many other concepts are on the drawing board to complement GNSS with LEO systems, dedicated or not. This is however a first demonstration that paves the way for other projects.