“Design and implementation of 4.3BSD” is actually the book name :-). It is an old book, but I guess it is still relevant. I don’t know how it compare to OSDEV.
The minix book is, I think pretty expensive. Amusingly, the “unavailability” of minix outside of the training book at the time is the reason why Linus Torvald created Linux.
You can get book resources here, for instance
I guess there are plenty of other options. Maybe also asking in a Unix subreddit?