oopsies guys sorry, turns out if you sort on the frontend after the results, it'll appear is if you're a dummy...

getReviews() async {
    await BookReviewsController().getAllReviews(false);

    if(mounted) {
      setState(() {
        reviews = BookReviewsController.bookReviews.value;

        reviews.sort((a, b) {
          if(a.timePosted > b.timePosted) {
            return 0;
          } else {
            return 1;
          }
        });

        filteredReviews = reviews;
        isLoading = false;
      });
    }    
  }

if you have this issue, don't be a dummy, check ya code :/