It has happened multiple times. I explicitly unfollow someone, never interact with them in any way, and then they again pop up in my feed after two weeks. Somehow if you follow too few people, Facebook just picks some more people for you to follow without ever asking you or telling you.
The behavior you are describing reminds me of the behavior that happens after deactivating your account, not deleting it.
I deleted my facebook last year so maybe things have changed.
My main goal was to harm Facebook's ad business, so I still accomplished that. As far as privacy, I've mostly given up on escaping from Facebook's databases.
My feed went back to being social rather than emotional manipulation or clickbait news. It was amazing.
Eventually the site lost its value for me because 75% of my real friends deleted their profiles, so it was an awkward/depressing ghosttown. I eventually deleted mine because of ethical qualms.