There is too big a difference between the amount of light around the lights themselves and the other areas of the city where no artificial light is lighting it up. The way to deal with this is to take the photos at dusk when there is still enough light to show detail in the unlit area but also when the lights show that they are lit. The other way (if you can do it) is to take 2 photos, one during the day (preferably BEFORE dusk but close to it) and the other at night, then overlay them together in editing software. This though demands that the camera (in the case the phone) be on a tripod or some kind of support so that the 2 pictures are exactly in the same position.
Otherwise, I'd say create a composition playing to the lights, put your phone's camera to -1 in it's exposure adjustment settings and see if you can make a nice photo with just the light's patterns.
Yes, i am a pro photographer.
BTW, a long exposure, while giving good detail on the ground would blow out the lights. They will look way too light, and most likely blurry and have a lot of flare. Yes you actually DID do a very good job with what you had to work with.
