Slang was words repurposed in meaning. Had been for thousands of years. The fuck is a "delulu"? The fuck is a "gyatt"? This is a symptom of terminal online-ness, like kids addressing groups as "chat".
i don't think you're defining that correctly. Isn't slang literally just defined at it's most simplistic as "terms used in non formal communication, that are understood between a group of people, due to collective contextual understanding."
I.E. workplace lingo would also be a form of slang.