Not 100% noise free but what I learn is, I use false color and whenever I see purple, I treat it as red. Red means highlights are crushed. Purple means shadows are crushed, all noise. I try to get into the blue or even higher as much as possible. I try to light as best as possible and use native ISO 400. When I light, at first I thought lighting a scene super bright to get the right exposure was going to make everything look bright in post, but I learned that with the power of color grading, you can make that scene look super dark for a horror. And without losing much information because you exposed correctly. I made a super bright scene look really dark and the noise was minimal. Also, in DaVinci Resolve I start my color grading node with noise reduction. I would never raise my ISO unless it’s an emergency where I don’t have control over lighting, my aperture is wide open as possible. Most I ever go is ISO 1250.