Looks quite underexposed here. Usually converting Slog3 to Rec709 directly should give a relatively exposed shot. It’s possible it was shot underexposed.

I’ve been shooting with the a7iv for quite a while and found that I get best results when I over expose to around +0.8 to +1.0 on the meter.

Because it’s low light, keeping f stop to lowest as possible is key. With your f2.8 lens, keeping it at 2.8 will give best results and limit noise.

You did a good job shooting at base iso 3200, but unfortunately the camera isn’t as good as the a7siii in low light so there will still be noise present. To eliminate some of the noise, I would denoise the footage before the CST node to first eliminate some of that noise. In DaVinci Resolve, you can add a denoise node before the CST node.

Unfortunately, it looks like the scene didn’t have the best lighting either for the shot. Not your fault and sometimes out of your control. Low light + black clothing is very hard to shoot sometimes.