One of the things I like about Tolkien writing his series from the perspective of “its a translation from Westron” is that any time he uses ‘Christian’ speech (words like evil, dark v light motifs, demon–words that are specifically coded from what is a common view from Christian Europe) is that that doesn’t mean things were actual demons. He did what translators would do: write it to make sense to the people reading it. It also means that because we do not have the ‘original’ text (because it never existed except in his mind), we do not know what the proper words or descriptors are in Westron culture. We just know what the generic sense is, what its supposed to evoke.
This little part of his writing makes it so masterful. It means that we as fans are also given great freedom to read in between lines and fantasize as we like. It goes back to Tolkien’s comments on what fantasy is: fun. He provided us a translated text and it means we can create many variations from how we want to read the mysteries in between.