Since 2020 I've kept notes on books. It helps me pay more attention to what I'm reading and is a good resource when I'm trying to come up with recommendations for friends.
I try to summarise books in three sentences, something I originally borrowed from James Clear's website, but I'm not strict. For someone with memory problems, it can be a fun exercise to try to summarise a book in only three sentences!
I have a to-read list if that interests you.