I've had a fix!

I've found the right incantation to enable the right agps on the #pinephone to get a fix in a reasonable amount of time (it was almost instantaneous, but the phone had been outside with gps but not agps-msb enabled for quite some time)

The script I've used to enable everything is:

#!/bin/sh

mmcli -m any --location-enable-3gpp
mmcli -m any --location-enable-gps-nmea
mmcli -m any --location-enable-agps-msb
mmcli -m any --location-status
mmcli -m any --location-get

(of course the last two are just to see that everything is setup correctly).

Now, I need to find out why Maps believes that the location services are disabled, and Settings is telling me that they are enabled…