The max volume doesn't help with songs that are far, far louder than others. I have this issue in our coffee shop, where a song that was playing at a normal volume on my AirPods, is extremely loud on Sonos. We flag it and take it off the playlist.
Side note: Sonos is atrocious when it comes to functionality and reliability, and it has only gotten worse recently. I can't discourage people enough from purchasing their product.