I'm not at all sure about what Tolkien quite meant by 'evil'. Certainly, there were indications of greed, and non-sexual lusted avarice, in the context of profound egocentrism or narcissism.
Certainly, by 'vibe' (for lack of any clear tool to crisply characterise Tolkien's sense of 'what' evil was exactly), then Nazgul, Yrch, Balgrog characterise features of evil, especially Nazgul.
Dragons on the other hand? I understand they fought for Morgoth, then for Sauron, but I've not had a crisp sense of 'why' or 'what' it was about them that was evil. Certainly, I 'get' that they eat Elves, humans and so on, and operate as agents to extend a Dark Lord's realm. I suppose that makes them 'evil' at least by proxy.
But if I look into the Silmarillion, there I see Glaurung mostly beguiling, making things forget themselves, burning up Elves to make room in an abode, and flying through skies during Dagor.....up to 5 (I forget when they got wings). These things make them ****ing scary in an encounter, but not like the screech of the Nazgul.
I don't know at all how to respond to the opening post in any prescriptive way
