Live programing is different than pre-recorded. Therefor, the ads used should be different.

Overlay ads, like what used to appear on TV, would make sense. Either shrinking stream (like Twitch did for a brief period), or having a dedicated portion of the screen they would overlap (so streamer could plan accordingly). But visual only ads, no audio. The benefit is that viewers are more likely to actually watch the ad too, instead of switching to another activity, as the content they're involved in is still going on. Even if their attention is more on the stream content, at least they will see the ad. Better than muting and seeing nothing that many people do now. Plus, far more importantly, the content is continuous, and thus of quality.

When Ads happen for pre-recorded, they are a time inconvenience to the audience. But nothing further. You pick up where you left off.

When Ads happen for live content, they interrupt the broadcast, and make the user miss content. Some streamers will put their stream on pause, but then that's just basically penalizing paid subscribers.