You've done so many things it's hard to tell what the problem might be. Possible cage was rotated past a stop, is routed incorrectly around the pulleys, or over part of the cage instead of going between the cage and the pulley. Need clear pics from side of derailleur, would not hurt to see video of rotating pulley cage. Bike part names can be easily found with a search rear derailleur diagram for example, also easy to google a pic of Shimano 105 rear derailleur.