Hot Take: Just because a show doesn't include every part of a book, it doesn't mean that it's not an adaptation just because they made changes you don't like.
Especially, if it's meant to be a contemporary romance. They are going to recontextualise some things to fit with our contemporary. Not to mention, some scenes sound really good on paper but don't sound as great when actors say them.
An adaption is just a piece of media that is based on a different piece of media and changed for a different format. If the writers and directors can explain the changes and why it makes sense for the new format, then it's still an adaptation of the source material.
Being disappointed that your favourite scene didn't make the cut (which happens for every adaptation) or a character doesn't look exactly as you envisioned in your head is totally okay, it's normal. But that doesn't mean the media is suddenly not an adaptation.
I am ranting here a bit, because a new show came out based on a book and there were some changes made considering the book came out in 2014. They recontexualised a few things, which for me was good considering one scene is like "hot and possessive" but doesn't make sense for the character's relationships or how women are treated in media. But some fans have gone completely off and are filling comment sections of people saying they like the show by telling them actually "It's completely trash and not an adaptation". They still kept like the major plots and the characterisations.