ATAD!
I have been there.
First thing: don't worry, you may need several more pass-throughs before being ready to declutter an area totally.
Second: if you take a bit of a break from the Big Project and just glance around for anything, anything at all, that is garbage, broken, stained, stretched, ugly, for sure you will find one thing. There will be that dried out pen, that broken ruler, that woven basket that is unraveling, the novel you didn't like so much after all. Socks with holes. Chipped mug. Dead houseplant. Scissors that are dull. Stretched-out pair of tights. Shoes that you never wear because they hurt. There will be one thing. Throw out all garbage first. Top priority.
If you religiously hunt for SOMETHING to throw out, every day, eventually your plateau will end and you will not have made the clutter worse in the interim.