>Personally, I find the lore and the universe of Hobbit / LOTR a bit dull. I haven't read the books, I've watched the movies as a young teen, but the universe just didn't interest me that much.

How much can you know if you haven't read the books? It's fine not to have liked the movies, and it's fine not to want to read the books, but maybe don't make such sweeping statements about a universe you barely know.

Anyway Tolkien's worldbuilding is unparalleled when it comes to his attention to language - very idiosyncratic in that way. Theology as well.

Another unique feature of the legendarium is that while Tolkien himself only published two books set in that universe, we do have access to a whole hoard of other writings of his thanks to his son Christopher - a view into not just the finished product (which in some cases, ie the Silmarillion, just does not exist anyway - or at least wasn't finished by Tolkien) but into the process of writing. Readers have access to the kind of material that would normally be reserved for scholars, and perhaps not even them.

Edit: regarding your tastes... Eh. Tolkien writes some dark stuff (Children of Húrin being the prime example) but not full on grimdark à la GRRM. Not particularly grounded either.