I don't think you can easily change the UI if it has not already been ported
I think this is the repository of pure maps
https://github.com/rinigus/pure-maps/issues
check all the issues both open and closed
as I can understand the app draws the data from the DBus, so the OS is responsible for delivering the data to certain DBus interfaces
the DBus is explored easily with qdbus which is easily installable under Plasma
a most complicated way is dbus-send
under Plasma you will find everything on the DBus, that is the modem for calls sms internet, sensors etc
you should find similar dbus entries under Postmarket, if not then the OS in not registering the GPS on dbus for some reason, maybe missing some package
I think this is the repository of pure maps
https://github.com/rinigus/pure-maps/issues
check all the issues both open and closed
as I can understand the app draws the data from the DBus, so the OS is responsible for delivering the data to certain DBus interfaces
the DBus is explored easily with qdbus which is easily installable under Plasma
a most complicated way is dbus-send
under Plasma you will find everything on the DBus, that is the modem for calls sms internet, sensors etc
you should find similar dbus entries under Postmarket, if not then the OS in not registering the GPS on dbus for some reason, maybe missing some package