This is a well-researched article on the Second Temple-era collection of apocalyptic works generally known as the Book of 1 Enoch.
I would take with a grain of salt the sweeping claim that angels have no free will or autonomy in Judaism. Generally true, yes. The Watchers myth, found in 1 Enoch and elsewhere (e.g., the Book of Giants) is an important counter-example. I see nothing gained by claiming the story isn't meant "literally."
We might have a conversation too about Belial and his angels in the Qumran texts.
But that is a quibble. Overall the article is quite good and informative.
There are many, many PaleoJudaica posts on 1 Enoch. Too many to link to here. Some recent ones on a range of topics are here, here, here, here, here and here. And follow the links for still more.
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