Responses
Maybe this one? Though I'm not sure if it already counts as "old"
https://www.mangago.me/read-manga/the_mountain_branches_dream_of_goblins/
beta
Old BL manhwa about ML (dark blue hair) who belongs to a past korean historical era and he travels to the future and meets with MC (orange curly hair)
It used to be kinda popular back in the day...