I have two suggestions for global contest. As you know the normal community members will be helping to flagging and directing the streamers subs to the correct link. I think these may help the subs to the right place.
Maybe make the streamer a video of how to comment on their giveaway thread.
Soundcore can provide the streamer a direct link to the thread and post the thread around the time the streamer is posting their stream contest. This way it will help the subs to go directly to it and less confusion for them.
Any other suggestions to help the stream contest???