The Silmarillion is basically unreadable.
I've read it twenty times
I'm sure there is a good story in there somewhere, but it needs someone to turn it into an actual book.
It's obviously not quite finished, but it's Tolkien's main work. He started it well before he even wrote The Hobbit
. It's the major work of his oeuvre. The guy invented an entire mythology all on his own, and that is a towering achievement worthy of immense respect.