Giant Neostrack App and Route Creation

Have you tried 'Ride with GPS' Don't know if its compatible with your unit but you can save and edit routes, and download (upload?) .TCX files. I use it with a Lezyne GPS and it's a bit more user friendly than Lezyne's own route making app. It also has loads of ready made routes available which are handy if you're holidaying in unfamiliar territory.

I have had a Neostrack for over a year, really pleased with it as I got a deal and it was just over £100.

I use the route facililty and it works fine for me.  The app is a bit weak, never really sure it does what you think.  I can always find routes I have created on the unit though, but like you say, they seem to vanish from the app.  They are probably there somewhere, but someone in the dev team didn't think people would want to access them again.  The mapping itself is a bit behind Strava I would say, I have got into the habit of creating a route on Strava first, it seems more able to navigate on realistic terrain.  I was planning an off road route on the South Downs and Strava was much better at finding trails I know exist, and not putting in ridiculous three sides of a square detours to get round some "break" in the trail.  I haven't find a way of just uploading a route created in Strava to neostrack though.