Here’s my take on this.
It’s a common issue, and whether you can recover the posts really depends on timing. Your primary method is Facebook’s own “Trash” feature. When you delete a post, it’s moved to Trash for 30 days before being permanently erased. You can access this via your Activity Log in settings. If you’re within that 30-day window, you should be able to restore the posts easily from there.
The challenge, of course, is that if more than 30 days have passed, Facebook considers the content permanently deleted, and recovery is generally not possible through their platform. For the future, using the “Archive” feature instead of deleting is a safer way to clean up your profile, as it simply hides posts without removing them.