I had no idea the Youtube was “normalizing” volume all this while. I switched this off on my Apple TV and LG Oled, as I prefer bit-perfect audio as much as possible.
does it sound better this way - yes I think so… 
I play movies and music from my NAS. the VLC app also has some kind of pre-amp setting, which I have set at 0 DB gain… It is set at default at +6DB Gain. Blimey
Hope I can get bit perfect audio out of that too?