I am also trying to write a minimal qml app that uses the built in GPS to retrieve current position. I am not sure if I can use Qt positioning or if I should just parse the raw output of the GPS myself, like the OP did here, and extract the position manually. It seems very dirty to do it that way, I thought there would be a nice API in QML that I could use. Anyone can point to a simple example?
If you're still struggling with this if possible try sharing a real piece of the code. It might be something trivial that doesn't show up in the example (which looks fine). Or at least a MWE that reproduces the problem, since I could not run your example, since it's not complete.