Expressing admiration at other people’s achievements is good, but you don’t need to diminish your own through comparison. Writing is a bloody difficult endeavour, regardless of the specific context. OP has mentioned that in their view, it’s easier to write lots when you’re basing it off of an established work, but even beyond that, different styles of writing have different objectives.

Completing the draft of a book in a year is an impressive achievement that you should feel proud of, and I think we should use our shared understanding of how difficult it is to make something to build up ourselves and other creators.