The 4G tower about 500m puts out about 5x what my phone does. I shielded my bedroom with the paint and its close to zero now. I'm not really thinking much about 5 yet, too early for my area. I do agree with your statements.
Did you also paint the doors, windows, ceiling and floor?
If you want further information, talk to the people who build shielded rooms. Cutting down EM radiation by more than a few db is incredibly difficult.
Plus you can't effectively earth something when your earth leads is multiple wavelengths long (eg at UHF)
Regarding "not treating the the floor", how to you prevent reflections? If there's any metal beneath the floor it will reflect the signals into the room.
Whatever, if your meter is reading "less than background" then it is clearly misleading you.
How did you come to the conclusion it disrupts sleep?
But hey it works for me, enough that I invested significant time, effort and a bit of money to get a decently shielded sleeping area.
I have better concentration during the day in these same low emf conditions too.