I have a full cPanel backup on my computer. It's from a Wordpress website that I built half-way. I want to extract the posts and move them to a new blog I'm building. If this is what you can do, hit me up on Telegram @Cyberczar.
As you probably know, the Wordpress posts and pages are stored on the database, in a table called wp_posts. If you have a database dump included in a backup, you can spin up a VM, set up the default root/<no password> combo for the database, restore the CPanel backup there, and then access the DB to SELECT the posts by their ID. The posts are stored in HTML format so you can then dump them into an SQL backup and then import them into a new database.
But it would probably be easier to use plugins like UpdraftPlus, XCloner, and the like if you had a live and internet-connected (that is, not localhost) version of the site.