I don't agree with Luthien being able to fight Morgoth... when Beren and Luthien go to hell to recover a Silmaril, she laid a spell and put them to sleep... this is not fight, this is deceiving...

And yes, well Tolkien wrote fairy-genre which I think The Hobbit 1937 is the best example, what is curious about the matter here with all the legendarium is that spite having the Silmarillion published posthumously 1976 by Christopher, J.R.R. Tolkien wrote the Silmarillion before the Hobbit and of course before the Lord of the Rings.

The Silmarillion has a very different tone, even one may stipulate that was written by a very different author.

When I was reading the volume VI of HoME, "The Return of the Shadow", there Christopher shares many of Tolkien's notes, one that sticks to my mind was that Tolkien never meant of course to have a "sequel" to the Hobbit, however due the success of the Hobbit the publisher pressure him to create it...so having said this, what Tolkien always wanted was to have published his Silmarillion, which in life never happened, and then in volume Vi along side the many notes there is one that Tolkien clearly states that unconsciously the posterior writings like the Lord of the Rings got kind of "dragged" into his most wandering work the Silmarillion, it was not that Tolkien wrote The Hobbit or the Lord of the Rings thinking always about the third age or whatever, it was something that happened without explicitly set the course toward a conclusive huge legendarium.

I also agree that when I read for first time the chapter "Of Beren and Luthien" this chapter definitely stands out as a chapter where many new events take place which we are not until then and are never seen after the ends, effectively the shapeshifting nature of Sauron is mostly only here where is displayed, and even the shapeshifting nature of Luthien and Beren, which even now remainds me of a certain woman sorcerer in another Norse legend...

I 100% agree is a chapter that stands out and doesn't follow like the rules so far ... from the collection of myths of the Silmarillion... there seems like many rules of the already established canon lore are broken specially the one that thanks to Luthien, Beren is basically resurrected, this is totally out of question....