this addon is aiming for usability, and removes the ghosts. the reason why you still see ghosts and stuff is probably because gm_construct beta v1 infects your other maps too. uninstall v1 and then play v2 and you shouldn't encounter any ghosts.

they arent ghosts. in v1, they are elements added into the map by the author of the addon. if you're so scared of it, decompile the map and delete the spooky elements. they arent ghosts, there are no ghosts.

here's a reddit post of me explaining about the black figure https://www.reddit.com/r/gmod/comments/vdcjuf/explanation_of_semper_the_black_figure_and_why/