I did the same thing with my 2013 X5. Pulled out of the garage with the trunk lid fully open. Luckily the garage door and garage door opener lost the tug of war and not the X5.
I had similar damage to the wiper arm and cover. Cover was easy to replace. I bought the new wiper arm and couldn't take the old one off either. I think you need a pulley remover type of tool that hooks around the arm while pushing down on the bolt.