Not happy with Sierra's pubes.. but least they are blonde.. if bright..
View attachment 95746
Try dialing down the cutout opacity (under surfaces) on the pubes, to say 50-60% and see if that helps. It's not a perfect solution, but it's one I use on hair fairly often (usually not quite that much except for pubes) to make the hair look a bit softer.
And, along those lines, a trick I use fairly often with hair is to duplicate the hair, and rotate one of them very slightly, then dial down the opacity on both. This can give the illusion of more stands, it looks a little softer, but the 'doubling' helps offset the transparency. I'll also make the transparency on one hair model slightly higher than on the duplicate model, which seems to help sometimes.
That's a trick someone shared on the Daz forum that I use somewhat often, if I'm not happy with the 'baseline' look of the hair, which can in some cases improve the situation. The downside is that you have to change the poses on both hair pieces separately, but cut pose/paste pose can save some time there (then re-rotating the second one slightly). You can use one of the two models to push out a few 'looser strands' a bit farther, or for similar purposes, while maintaining more overall volume.