From a first look, I see three problems at once
- 0.8% frames dropped due to encoding lag (CPU overload)
- 0.3% frames dropped due to rendering lag (GPU overload)
- 0.1% dropped frames due to bandwidth problems
Suggestions:
- turn off Windows 10 Game DVR
- limit ingame FPS, so that the GPU never reaches over 95% load
- try to reduce CPU load (for example with the FPS limit, or by using NVENC instead of x264)
- check Network connection and internet connection for packet loss and bandwidth, maybe reduce bitrate slightly