Hi kizilyildiz
I use calibre, which is in the repo. It doesn't have the prettiest interface but it gets the job done. I usually search my library using book titles or authors' names, but calibre allows search using identifiers.
I didn't know GCstar, but judging by the screenshot above it has a nicer interface than calibre (thanks for the suggestion @palto42). However, it isn't available as a flatpak or a snap, and creating my own packages is a bit beyond me.
Best regards.