Also, the device path given by chrony is out of date and the one given
by gpsd works: that is "/run/chrony.XXXX.sock" instead of
"/var/run/chrony.clk.XXXX.sock". If I am wrong about the paths, I don't
know how chrony works, but only the former works for me.
chrony.clk.XXX.sock is a new thing in gpsd 3.25: it gives you the time from GPS serial messages (which is inaccurate but includes the time of day); chrony.XXX.sock gives you the PPS information (which is accurate, but does not tell you which second it is). See
https://gpsd.gitlab.io/gpsd/gpsd.html#_files
On many recent Linux distros, /var/run is linked to /run.
James