I don't think there is a solution for property sorting book titles etc. in Backdrop Views. In Drupal I was able to use the "Views Natural Sort" module so that I don't get a ton of listings under "A", "An" and "The". But this module isn't available on Backdrop.
Is there another solution for this issue?
Thanks for asking this question. Yes, I love this module as well. Being a librarian, when I discovered things did not sort correctly it bothered me. I am using it in Backdrop but have not moved the project to Backdrop Contrib.
I think that is the latest version. The D7 module has a submodule for sorting any text field. Views Natural Sort Text Field. That part does not work but the main module sorting title fields should work. Give it a try and let me know.