It seems to me that your problem was with your own feeling toward the list - “I felt proud about my list” - and not the list itself. Where does that feeling come from? It might be worth exploring.
It is true that one can be vain with oneself as the sole audience, but I wonder how common that case is. I'm going to give myself a pass on that, since the purpose of the list is mostly to remind me.
If you have a bookcase in a common area, do you take any thought to what's in it? I confess to taking a little: a bias in favor of hardbacks on one table; biographies and letters on a shelf; etc. (And I confess to being slightly flattered that when my son was working from home during the pandemic some of those he Zoomed with were favorably impressed by the books behind him, most of them mine. I did not set up that bookshelf to be a Zoom background.)
What strikes me as odd here is simply the lack of context. If you've read a book, tell me why you read it, and tell me what you thought about it. It's great that AG read The Inimitable Jeeves, but how did it stack up against Leave it to Psmith or Uncle Fred in the Springtime?
What are the purpose(s) of keeping a lifetime list of books read?
It’s not masturbatory to create goals for yourself, and lists are a great way to track those goals.
Having that data even allows future insight into things you haven’t even thought of yet.