Hi, I'm deleting the city_walls ways you wrongly added, the wiki is clear on this: https://wiki.openstreetmap.org/wiki/Tag:barrier%3Dcity_wall

it is NOT for mapping the walls of a castle, there is no point in mapping walls of a castle, the walls of the castle are already defined by the outline of the castle polygon. What  you are doing is mapping for the renderer
https://wiki.openstreetmap.org/wiki/Tagging_for_the_renderer