TBH, that's significantly better than I would have expected for photos of the stars taken on a phone.
FYI stars (and anything over a few hundred feet actually) is at an infinite distance as far as your phone's optics are concerned. So it's not a matter of focusing, it's a matter of trying to resolve what are effectively pinpoints of light on a black background while in your hand, where the minutest movement will smear them across the sensor.
Photographing the stars is not trivial, even with a real camera and a tripod.