Just listening to Episode 12, and concerning why Finrod is back there in Nargothrond: while he can and probably does still send up reinforcements up to Orodreth in Tol Sirion (which is imo very important, bc it is one of the major needle holes into beleriand), he is also the supply line, probably. He and especially Amras are, it is even specified in NoME, that they are basically in charge of the grain chambers and livestock economy. Also Finrod does go up with an army and supposedly drives back an army from Tol Sirion and goes to the Fen of Serech, but is then smashed by Sauron, at some point in the battle. I am of course still very influenced by the fanfiction i was co-brainstorming the timeline for this summer, so now i have about 3 separate canons in my head 😛
Concerning Glaurung, in the aforementioned fic the writer had this great idea of Glaurung getting the men of Dorthonion to kill each other and start to generally go mad in the villages. I understand that there is not a lot of room in this episode for this story, but in general there is a lot that Glaurung can do as a character & i don't think it does not always just has to be this one on one mind twisting thing, there might be something in scale or kind between the battering ram and the one on one corruption. Something like the dragon breath or its scream, looking him into the eye instilling fear and madness, twisting perception and thoughts in mass scale, not yet on the more personal level we get later. This larger area effects could also be shown a bit more easily, you don't need to have a big character have to meet Glaurung every time, it could be a sort of environmental effect in scenes. Maybe his voice could kinda reverberate over the scene in these moments, so we don't just see him casually dialogue outta nowhere. I really liked the suggestion of Glaurung throwing the thief back at Caranthir too, or maybe saying sth like "Yeah and you earned all your wealth here huh" (in a more eloquent way) There might be a way to kinda phase in his speech like that naturally, and without dedicating a giant scene to it.
Edit: I also am very pro Sauron at Fen of Serech. The swamps are always such a good territory for the baddies, it was like one of the first things melkor did in the marring, stagnating the waters, and cursed swamplands are present in the legendarium. Anti-Ulmo territory, so also good anti turgon/finrod territory right? I love him catching Finrod in the swamp there and maybe toying with them a bit, but just by a bit not getting him into his claws, because of those pesky Beorians. A little inverse Lay of Leithian prelude.