I use the NVIDIA "Latest" setting for SR which means on Quality and Balanced, it uses preset K, and on Performance and Ultra Performance, it uses presets M and L respectively.
All modes I've tested exhibit some level of noise/pixelation on foliage. GTAO Low is practically unusable on all modes due it already having a low sample resolution which results in the most artifacts. GTAO High is slightly better but artifacting can be distracting in certain areas where foilage is not in direct sunlight.
I found that SSGI has better stability, especially SSGI High, but is more expensive to use. To make up for this I use it together with Performance (Preset M). It's not too distracting and performance is still decent.
I also noticed that TAA does the best job at denoising the image; using it with GTAO High or SSGI results in no artifacting or shimmering whatsoever. However, the biggest issue with using TAA is the blurry image and ghosting it causes, and so it's not really ideal for me.