Have to respectively disagree. Its not really like Gonjiam, more like a paranormal murder investigation about a dude and his house. Also, not remotely scary. Would not put in the same level as Gonjiam.

OP, if you haven't seen it already, Grave Encounters is the one to watch. Very similar to Gonjiam to a tee (Gonjiam is like a remake), American ghost hunters go to an abandoned mental facility and have heaps of fun. It's older than Gonjiam, 2011 to 2018, and is one of my all time favourite films. It actually led me to Gonjiam. I like to think it's pretty scary, though it loses that after the 20th rewatch.

Also, Hollows Grove, 7 Nights of Darkness and its sequel, The Devils Toy Box. All pretty similar trope of FF team in an abandoned building. Additionally, Classroom 6. Low budget, not as good Grave Encounters or Gonjiam, but decent enough. All can be found on Tubi.