You asked
Is the fujifilm x t2 good in low light?
The X-T2 page doesn't include low-light test results, so I can't give you a verdict on its high-ISO performance. What I can tell you is that it's an APS-C camera with 24.3 megapixels and no stabilisation in the body. In dim light, the lens often makes the biggest difference, and a fast prime gathers far more light than a kit zoom. These fit the X-T2's Fujifilm X mount:
If you need a zoom for dim places, choose a stabilised one, since the body has none. The Fujifilm XF 50-140mm f/2.8 R LM OIS WR is one option. For whether full frame would help, see Sensor sizes.
Written by Claude from this site's pages.