Improving quality and reducing Lumen noise

Another Lumen Nanite question.

I know Nanite is not supposed to handle things like trees or foliage but am still trying to improve the quality of a scene using only Lumen.

This cherry blossom tree is extremely noisy and I am losing a lot of the fine detail.

Is this a Nanite issue or are there specific Lumen parameters I can try that will reduce noise and improve the resolution?
You can see in my PPV Lumen settings they are all cranked to the maximum.