Post that populates itself (almost) automatically using data from imported excel file

Sounds like a single “book” post type would be most appropriate. You could then add custom postmeta, which does not require Advanced Custom Fields. I would create the post type and custom fields first, test them out to make sure they’re saving appropriately to the database. Then, you can do a foreach loop for each line in your CSV, and use wp_insert_post which has a meta_input parameter where you can add all the corresponding custom fields (postmeta).