So ... we only use YouTube live for our initial stream.
Here's our flow:
Blackmagic ATEM Switcher
Embed into Church Online Platform
At the Wirecast level, we also record the service so we're able to archive our messages for viewing/listening later.
As far as I've seen, Youtube doesn't "scan" a Live broadcast for copyrights until the broadcast has ended. If the video contains copyrighted material (in our case, pre-service music, sermon bumper video music, etc), it will mark it as "includes copyrighted content" and any subsequent play will include ads. It will also give you the option to remove the song or file a dispute.
Since we don't use Youtube to archive/playback, we just remove the video from our channel.
This article is helpful: