This is what the YouTube Help page says. I guess go with Normal Latency.
Normal latency
Best for: reduced viewer playback buffering.
Choose "Normal latency" if you don't plan to interact with your audience. This is the highest quality setting for viewers since it has the lowest amount of viewer buffering.
All resolutions and live features are supported at Normal latency.
Low latency
Best for: near real-time interactivity
Choose this option if you want low latency with minimal viewer buffering. This setting is a good balance between the other two options.
This setting does not support 4k resolution.
Ultra-low latency
Best for: highly interactive live streams with real-time engagement
Choose this option if you want to maximize engagement with your audience and don't mind increasing the chances that your viewers may buffer more.
This setting does not support DVR, 1440p, and 4k resolutions.
Note: live ingestion issues on your network will affect viewers more in this setting. Consider decreasing your ingestion bitrate to ensure that your network can sustain the stream.