The poor adaptation doesn't necessarily mean it's bad; Jackson needed to recoup his investment and convey the atmosphere. He managed to convey the atmosphere, at least 50%, especially in the first film, less so in the third. But it's understandable, as the third film has more large-scale scenes.

As someone who has read almost everything by Tolkien (sometimes even in the original, but only individual chapters, as it can be a bit challenging, and the Russian text keeps popping into my head), I'd like to share my opinion. The books are amazing and have no equal in the world, except perhaps Dune, but that's already science fiction. The incredible coherence and thoughtfulness of the world, which combines various mythologies and the personal ideas of the author, a perfectionist.
The film is a complete disaster; neither the idea, nor the spirit, nor the characters are preserved (the role of the valiant Boromir is played by the lover of Lady Chatterley, and he should be punished for that). Everything that could be ruined has been ruined, perhaps with the exception of Gollum. Personally, I put Peter Jackson in the same category as George Bush and Bill Gates, and this is definitely not a list of Christmas greetings. He simply took the saga and turned it into an ordinary Hollywood blockbuster. But it is possible to adapt works properly. For example, Dune has already been ruined twice, but Children of Dune turned out quite well, although not without flaws. And the most striking example is the Ring of the Nibelungs (from which the One Ring was taken). With a meager budget, we get a magnificent film in which ordinary models act much more convincingly than movie stars, and Kristanna Loken is simply perfect in the role of Brunhilda. (Those familiar with the German epic will understand.)

By the way, didn't she ask Aragorn about Arwen in the book? (I read it when I was 12 - I don't have time to reread it now - I don't remember anymore...)

Arwen appears specifically (and not indirectly, through hints) only in the third book, and there are no romantic scenes from the first film in the book.