If it’s not a famous book, you may find some Goodreads reviews and if you’re lucky a Reddit post or two, but not vasts amount of online discussion like you’ll find about any passingly good series or movie.
And if you love a movie or a tv show, it is much easier to convince people in real life to also watch it, since it’s way less time consuming and not everyone even reads books, but most people watch movies.
I just think that this really sucks about reading books.
You need a book club. Unless you’re friends are particularly book people, you’re not going to be having the same experiences with your reading. People are funny with reading books, we’re all over the place and we can only read so many at one time. If we don’t feel into it we’re not going to commit that time to it, but if you’re in a book club where people go just for that experience, It should work.