I really want there to be an onsen cutscene on Planarcadia. Given Evanescia already went for the "crash-into-hello" teen rom-com trope, it wouldn't be a stretch for her to do some hot spring tropes.

Only issue is Hoyo would need to make two alternate scenes if they have the Trailblazer join in, one for Caelus and one for Stelle, since I doubt Hoyo could show mixed bathing with the game's age rating.