There's no comparison. The A5100 is an APS-C format mirrorless while the G7X Mark ii has a much smaller 1" sensor. This difference alone means that the ISO performance of the A5100 will be superior to the G7x ii. Here's a comparison: https://www.dpreview.com/reviews/image-c...
Furthermore, because the A5100 is an interchangeable lens camera, you have the ability to use professional quality lenses that will be vastly superior to the G7x Mark ii in sharpness, light gathering (i.e. larger aperture). Plus the larger apertures that are available on the A5100, along with the longer focal lengths that the A5100 must use due to the larger format, will allow you to get a much shallower depth of field whereby you can blur out backgrounds much, much better than what you can do with the smaller-format G7X Mark ii.
There really is no comparison between these two cameras. Not only in terms of sharpness, bokeh, and distortion, but in terms of creative capabilities, too. The A5100 is simply a much better image-making tool than the G7X Mark ii could ever be.