The LG G6 wide-angle rear camera doesn't do well in low-light due to its relatively slow aperture, and the lack of OIS. This is a phone camera after all, not a mirrorless camera with a micro four thirds sensor. The small pixel size of the camera sensor requires a very fast aperture in order to perform at its best. You can always increase the ISO speed, but this will have a very negative effect on image quality, especially as you pass ISO 800, at least on most phones.
As you probably already aware of, the LG G6 comes with two lenses, which serve as two separated cameras. One camera with a 71° wide-angle f/1.8 lens and an optical image stabilization, and a second camera with a 125° wide-angle lens with a f/2.4 aperture lens and lacks an optical image stabilization. Both cameras use the Sony IMX258 Exmor RS image sensor that has 1.12µm size pixels.
As you can see, the pixels of that IMX258 sensor are very small, which means that they can't capture a lot of light. The camera with the 71° field of view (let's call it 'the regular' camera) comes with a f/1.8 lens, which is 2/3-stops faster than the f/2.4 lens on the wide-angle lens. This translates to 1.78 times more light, almost one stop different, which is significant. The regular lens camera also uses an OIS system. This optical stabilization system can improve the low-light performance. It does that by allowing users to shoot at slower shutter speed but counterbalances for camera shake so your images will appear sharp and in focus. If you take the same image with the wide-angle lens with a slow shutter speed, the chances that they image will turn out blurry.
The results are quite evident and I've seen images taken with the wide-angle at low-light conditions, and you can clearly see that it struggles in those type of lighting conditions. There is no magic here, the slower f/2.4 aperture just lets less light through compared to the f/1.8 lens. If it wasn't hard enough for the f1.8 to perform well in very dim areas, it's even harder to achieve this with a f/2.4 lens. Of course, it really depends on the scene. If you are shooting at night with a good ambient light source you shouldn't have a problem. However, when you are relying on available light but it's lacking in the scene, you might get a relatively dark image, even a blurry image. There is an option to shoot a long exposure shot, but you have to put the LG G6 on a stable surface or user a tripod to be able to obtain a sharp image.
So the wide-angle camera has its disadvantages and something that you should be aware of. Shooting with a wide-angle lens with the LG G6 can be really fun because you are going to capture shots that with other phones you wouldn't able to get. This opens up a whole new world of creative possibilities for enthusiast photographer, or just anybody who like taking pictures of landscapes views, indoor shots, architecture and it's amazing for street photography as well.
Just keep in mind that it's not that you are going to get a very dark image when shooting with the LG G6 wide angle camera at night, but the camera might use a high ISO that will make your still, as well as your videos, look grainy.
Here is a LG G6 low light sample video that was shot by Max Lee using his LG G6 with the wide-angle lens. The reason I post it here is because it was shot in relatively low light, so you get to see how the wide-angle camera performs in low-light. you can clearly see that the video is quite noisy and struggles in areas that are not well lit.
So as I said, know the disadvantages and see whether the LG G6 camera fits your shooting style. I probably would be shooting with the f/1.8 lens at night and use the wide angle lens in good lighting conditions. However, sometimes you just want to get a good wide-angle night shot, the G6 camera can achieve this, but it's important to know about its deficiencies.