I started finishing more books when I started counting the books I finished instead of counting the books I abandoned!
This is good advice and also: allowing yourself to abandon books. Not every book is for every person! It's okay to say "eh, this isn't enjoyable/useful for me" and DNF! It's even okay to say "I only enjoy/need part of this book" and DNF even though that part was good!
I don't think everyone has this problem but I can get a bit "can't eat dessert until you finish your broccoli" about reading and then give up on all reading for a while rather than admit to myself that a book isn't "challenging" it's just super boring