Powerful CPU and/or hardware-encoding capture card as a source?
Consider GPU transcoding below if you have multiple applications open on your streaming desktop or a HARDWARE video capture device. If you can not, streamline operations on your single device, so your other application doesn't affect too much CPU/GPU. More than that, you better quit all other applications as they use your CPU and GPU, leading to artifacts in your video output. Your streaming computer must be dedicated to that for the time of your live stream and recording. Use a different computer for streaming and operations (for a DJ or a video game player, for example) whenever you can
Available resources (CPU/GPU), slow encoding, long keyframe period, and network buffer are way more important than resolution and bitrate, which are usually only the settings you are recommended to change by streaming services for their comfort (less transcoding complexity for them means less cost) Nobody knows streaming is late when there is no real-time interaction except for the broadcaster. You should care about latency only if interaction matters more than video quality. The slowest you encode and transmit, the better quality you will get, as you provide more room for the encoder to “ look ahead,” meaning it can look at what's coming before encoding to optimize encoding. Encoding is like sex: faster is not better.