The bottom strip of the Primaries palette has a Shadows parameter that lightens shadow detail while leaving the midtones alone, and a Highlights parameter that recovers bright detail and blends it into the unadjusted midtones. Together they let you open a dark frame without moving the ends of the range much.
Contrast uses an S-curve by default (the Use S-curve for contrast setting in the project settings), so raising it rolls the shadows and highlights off instead of clipping them. Pivot sets the point contrast stretches around; Blackmagic suggests a lower Pivot on darker images to avoid crushing the shadows as you add contrast.
Give each job its own node. Press Option-S on a Mac or Alt+S on Windows (or choose Color → Nodes → Add Serial) to add a node, then keep exposure in one and colour balance in the next, so you can switch each off to see what it contributes. For a subject darker than its background, the cleaner route is a window on a separate node; our guide to brightening backlit footage covers that situation.
Noise reduction: Studio and free
Every stop of brightening lifts sensor noise along with the picture. In DaVinci Resolve Studio, the Motion Effects palette has Temporal NR, which averages across frames, and Spatial NR, which includes the AI-based UltraNR mode. Many colourists put noise reduction on an early node so later nodes work on a cleaner image. The free version does not include the Motion Effects palette, so there the defences are a smaller shadow lift, leaving noise-only areas dark, and keeping Midtone Detail at zero, since raising it adds contrast around edges and can make grain more visible.
Log and raw footage
Log clips look dark and flat until they are transformed, so set up the conversion before judging brightness. Either set Color science to DaVinci YRGB Color Managed in Project Settings and give each clip the right Input Color Space, or add the Color Space Transform Resolve FX to the first node. For camera raw clips, the Image tab of the Edit page Inspector and the Camera Raw palette on the Color page expose the raw settings, including an exposure or ISO control depending on the format, which is the cleanest place to brighten them.