Seems very much like a situation where you should keep out of other people’s business.
How about the families of the 5 people in that house? What should they be told?
"Sorry folks. I knew this GPU has issues and could possibly cause a fire, but people on the internet decided I was a bad person for doing the right thing, so I ignored the potential issue and didn't let the landlord know."
I hope you have a great life.
Mind your own business.