I don’t know what science you took but when I was taking my classes no one talked about an absolute anything.....deep space always had a partial pressure ....admittedly very small but still measurable
No such thing as a partial vacuum, is what I was taught, precisely for the reasons you stated in your first post.
https://www.youtube.com/watch?v=IV9w7zSNyOk
Though I don’t agree with this snarky Brit wholeheartedly, he nails this problem of how the earth’s atmosphere interacts with a vacuum of space and gravity, or not.