While I do not know the specifics to your questions, in the past Roku has advertised for the Miss Universe on either the day of the broadcast or the day before on the Home Screen. You then clicked on the advertisement and it would take you to the livestream channel. (they also showed replays on this channel for some time after the event as well).
The official website for Miss Universe is https://www.missuniverse.com/ (and currently has a countdown clock to the event) and Youtube also has an official page and has some pre-show things going on over there now as well. https://www.youtube.com/@OfficialMissUniverse/videos
