The second video suggests that the wobble is coming either from the adapter base to flat pier plate connection, or the flat plate to pier connection.
I think I¡¯d take a close look at those connections around the flat plate. Maybe the plate isn¡¯t flat, or something is giving the false impression that a bolt is tight when it¡¯s not fully tight.
If you don¡¯t have washers between the pier adapter and the flat plate, try inserting one at each bolt.
Good luck.
