As a bipolarbuddy this happened to me. It wasn’t the books, it was my brain. As you probably know a sign of bipolar disorder is starting book after book without being able to focus or fall into them. For me it was a sign to adjust my meds. Stay strong.
Stack them face down and spine to the wall so all you see are white pages. Take the one off the top (you won’t remember what it was if you have a large pile). Read at least 20 to 50 pages. If it doesn’t capture your interest you move it to the bottom of the pile or discard.