Please remind me how Draugluin is involved if Sauron’s crew isn’t participating in the Dagor Bragollach.I would love a scene of Huan fighting a dragon But I don't think it's easy to do - the hosts wanted only one dragon in this battle, and neither Glaurung nor Huan can die here. Could it be some form of withdrawal? Huan isn't afraid of danger or death though, and his big withdrawal moment is connected to Draugluin (who is looking to kill Huan) when Celegorm orders Huan to come with him and they flee to Nargothrond; Celegorm wants to protect Huan from his part in the Doom of the Noldor that we're revealing this season. And Glaurung probably shouldn't withdraw in three consecutive battles - he needs to win at least once before Turin's story.
Maybe their fight could be interrupted by circumstances, but it shouldn't feel like teasing the viewers and then denying them the action scene climax they were looking for.