Hello first of all there is indeed a denoising function in Daz so why dont you use it?
Steps to handle this issue can be:
Add more light or as this seems to be a night scene one or to lamps that brings more light. Noise is harder to fight the darker the scene gets from my xp thats a bit like in real life when you are in a very dark room and you eye is catching just glimples and your own vision gets fuzzy.
a video for how to use the denoiser which is under render filtering.
You must be registered to see the links
in the video he talks about that he doesent like it but you can change render resolutions and how many pixels are effected by the denoiser urself so you may wanan expereiment with that.
You also have some fireflies and may experience some issues with closeups of eyes in you scene to combat that you may set a bigger path lengt in the optimization tab to around 11 i think that fixes most eye issues at least. There is also the caustic samples if you wanna go with her into the pool at some point
.
I also would set the min update intervall higher as it is not needed to update the render every sencond and the 5000 samples are mostly not needed for good lit scenes so i would lower that if you see that you render image looks great and the renderer goes on for a long time. In your case tho upping the samples might be the right solution if everything else fails since with more samples you generally get less noise.
But upping samples means longer render times so try out some diffrent scenes and how much you need for diffrent settings to get good results.
And if your still following me a real bonus tip.
Render in lower resolutions and then use an app to scale the image up. there are some ways in gimp or ps or use google to find a tool that uses the nvidia ai upscaler if you have an nvidia card. That can save hours or render times and you get 4 k images for 2k render times with even the nice effect of it having a nice smooth effect that also kiills noise.
Have fun.