You asked
Is the fujifilm x t30 ii good in low light?
The site doesn't have a low-light test of the X-T30 II, so I can't tell you how its high-ISO files compare with other cameras. What I can say is that its 26.1-megapixel APS-C sensor is good enough for most hobby work, but full frame is the clear step up for low light.
The body has no in-body stabilisation, so the lens matters more. For dim scenes, a fast prime gathers far more light than a kit zoom. Primes are sharper for the money and much faster. Good choices from the catalogue include the Fujifilm XF 23mm f/1.4 R, the Fujifilm XF 33mm f/1.4 R LM WR, and the Sigma 30mm f/1.4 DC DN Contemporary.
Written by Claude from this site's pages.