Demon Slayer: Kimetsu no Yaiba - Tsuzumi Mansion Arc

I see this is doing the rounds on the net as people want to know how to see this "film" so they can complete the 2024 Top 250: https://www.reddit.com/r/KimetsuNoYaiba/comments/1hcp0di/demon_slayer_kimetsu_no_yaiba_tsuzumi_mansion_arc/ I had the same question myself. There seems some debate over whether it's real, and where to see it?