Hi CarolchiFBG,
I didn’t encounter any problem deleting the copies of master pages. How did you create them?
According to your second screenshot, the Berlin_copy(2).master is set as default master page, this could prevent you from deleting it. Please try to set another master page as default (In SharePoint Designer, right click on the master page you would like to use, click Set as Default Master Page), and then try to delete this master page again.
In addition, I suggest you check the settings for these copies of master pages from the Master Pages library, and see if you can delete them from there.
Any updates, please feel free to post back.
Thanks,
Evan Zhang