To add further into the discussion, I have a couple tour replays that demonstrate the difficulties Roaring Moon has with actually setting up. While scavenging through recent tournament replays, there’s been surprisingly few teams loading up with Roaring Moon, instead they opt Dragonite who imo is the best DD sweeper in the tier. Even when it does show up, it doesn’t make a notable impact, mostly winning games vs opponents whose teams are completely crippled beyond repair which says nothing about Roaring Moon’s alleged brokeness.
https://replay.pokemonshowdown.com/gen9ou-2115933352-sd15bu4lz486i6ry5axnmtytbea1bztpw
(Lando trades HP with Moon and U-Turns into Gambit to remove it)
https://replay.pokemonshowdown.com/smogtours-gen9ou-764807?p2
(Chaitanya is perfectly suited to checking Roaring Moon with Wisp Cinder, Whirlwind Skarm, and Mola)
https://replay.pokemonshowdown.com/smogtours-gen9ou-759306
(A seemingly free setup for Roaring Moon via Heatran is thwarted by the reveal of Will-O-Wisp)
To secret to dealing with Moon is good positioning. Even with Moon’s decent natural bulk, Moon is at risk of being burnt, para’d or put on a timer with Toxic. As shown in the first replay, what I said about Lando being able to U-Turn into a rkiller is valid, especially since Lando commonly pairs with Gambit/Raging Bolt. Even after taking chip, Lando is still able to Intimidate the Dragonite.
Like Finch said, Moon can force progress with Knock and raw attack power, with or without Dragon Dance, but it doesn’t have the potential to 6-0 well-built teams like Volc did with the correct Tera. Moon most of the time is running Tera Flying. While it can branch into other Teras (Ghost, Steel, Fairy), the reason you run Flying is to not lose to the bulky Ground types in the tier, especially Tusk who can potentially eat a +1 Acro.
+1 252 Atk Protosynthesis Roaring Moon Acrobatics (110 BP) vs. 248 HP / 4 Def Great Tusk: 388-458 (89.6 - 105.7%) -- 37.5% chance to OHKO