Just open a text file and write down the books you've read and want to read. All this complication gains for you essentially nothing.
Just because you only care about a small sliver of the product doesn't mean that others feel the same
To be more clear, when a database (with multiple fields, and better workflows) is clearly the right tool, why would you try to implement it one ad-hoc in a simplistic text file/editor!?
And if someone says Emacs+orgmode, that’s basically a nice framework for implementing applications backed by structured data stored in our format :-)
This is the kind of thing recutils is specifically designed for, where org-mode is merely capable of it by virtue of its kitchen-sink nature.
IMHO recutils should be the first choice if you find yourself wanting both a database and a text file simultaneously.
Plain (-ish) text is flexible and searchable.
I agree with the grandparents comment. I just use a list in Apple Notes.