For less than 5 Mbps, we set 25 frames per second, 5-10 Mbps — you can safely set 30-40, 10 Mbps and more — 50 fps
Also, imho, the bitrate recommendation is not very accurate. Of course, if your channel is good, set 1000+ and you won't have any problems, but unfortunately not everyone has a good internet connection. Therefore, the bitrate should be chosen depending on the game resolution. Based on personal observations, when playing at 1024x768, a bitrate of 700-800 is quite sufficient. At a resolution of 1280x720, a bitrate of 1000-1200. There's no point in setting higher output resolutions, as they will devour an immense amount of CPU resources. It's worth noting that the choice of resolution is key in streaming — you should base everything on it and adjust all settings accordingly. It is highly recommended to set the game capture resolution and the stream output resolution to the same value (this will prevent additional system resources from being spent). If your computer cannot handle the same resolutions, the minimum load will be when the output resolution is half that of the capture resolution. And by the way, if you play in fullscreen, the CPU will be about 5-10% less loaded.