I can’t think of a nice way to do this through QGC without running autopilot firmware (which you could do just without bothering to send it any motion control signals) or a custom QGC version.
If you don’t want to go the autopilot approach then a BlueOS extension could be useful, and wouldn’t even require a Navigator:
That said, if you already have (and want to make use of) a Navigator onboard then another option would be to make an extension using the new Navigator libraries. Hopefully we’ll have an example available soonish that does that anyway, since it’s useful functionality to show to people.