I use Kavita for my comic book collection, and recently added some books into it as well. Syncs well across devices. I don’t really read books as I have so much time to listen to them instead but I can’t see why it wouldn’t work for someone who does.
I’m a metal head, so these will be in a similar vein, though there is techno and more relaxed stuff at the end. Might add links if I remember later:
Chon, Animals as leaders, Polyphia, Plini, Syncatto, Intervals, Meganeko, Broke For Free
Boilr, was originally made for steam deck.
I’m an adult, I can do what I want.