I think the smacking isn’t new but was one of his less obvious/obtrusive nervous habits. It’s recently more noticeable because of the new mic.
He has so many tics and nervous habits. Smacking, swaying, picking/wiping, chat scanning, hair smoothing, throat clearing (my absolute #1 most hated), jiggling his leg(s) (noticeable when the chair starts vibrating around him), snorting ofc, cluttered/overly expository speech, ear wiggles. I’m undoubtedly missing a few.
Edit: His laughter is almost always a self-soothe so it counts, especially the cope laugh.