Hello Andrea,
I’m really sorry to hear that and was really looking forward to a happy conclusion, especially since the tests turned out fine. I have a sample over here of one of your own tracks, https://alexboia.net/test-gpx/, successfully uploaded and properly displayed, which is why this is all the more puzzling.
Thus, if I may be so bold, I would like to ask you whether you could grant me access to your WP admin: web browsers have some tools that can be used to track what’s happening behind the scenes whenever we’re doing something on a web page and I hope that being able to upload a couple of tracks myself and use those tools I can figure out what exactly is not working out for you.
I can understand if you are uncomfortable with that and, as an alternate, maybe we can establish a TeamViewer session and I could guide you through this process.
As for your other question, there currently is no shortcode, but it is included in the version I’m currently working on.
Regards,
Alex.