My upstairs neighbor's kid quit piano and got a drum kit, so I tracked how bad it got week by week in a notebook
Two years ago the family above me had a kid who played piano for maybe 20 minutes a day, and honestly I barely noticed it. Then in March they sold the piano and got a drum kit, and that first week was like someone kicking a dumpster outside my bedroom window. I started writing down the noise in a cheap notebook just so I wouldn't feel crazy, times and everything, and by week three it was 9 or 10 sessions a day. I went up and talked to the mom, and she said "he's just a boy with a dream," which is a hard thing to argue with at 7am on a Saturday. What finally changed it was when I showed the landlord my notebook with 6 weeks of times logged, because he took one look and said the drum kit counted as a lease violation. Now the kid plays on an electric kit with headphones on, and my notebook is sitting in a drawer feeling pretty proud of itself. For anyone in the same boat, did logging things actually work for you, or did the landlord brush it off anyway?
Man, I feel for you, that sounds like an absolute nightmare to live under. Honestly the notebook thing is smart because it turns "my neighbor is loud" into actual proof, and landlords can't really wave off a written record the way they can wave off a phone call. My sister did something similar with a barking dog situation and it worked, so your mileage may vary but it seems like paper beats complaining every time.