Despite Spotify's several canned responses, it wasn't Normalizing the volume, it wasn't the Crossfade, it wasn't the Download/Streaming quality setting, and uninstalling and reinstalling didn't help.
It was the Equalizer.
My old phone - Samsung Galaxy S7 - had not only an Equalizer, but also the "Customized Audio", which is evidently a Samsung-only product. Which I thought was great, btw! I wish Spotify would license that, or that Android would. My Pixel 2 XL only had a basic Equalizer, which I immediately activated and customized to my preferred settings. When I turned it off, the volume went back to as loud as I wanted it to be; when I turned it on, it immediately dropped by about 20% and sounded overall muted. Which is why other music services didn't have the same problem.
I can live without the Equalizer, but I'm thinking of downloading one since there are several out there that are supposed to be very good. Of course the problem may recur, so I'll decide then.
Does anyone have a third-party Equalizer app they would recommend?
I just took the suggestion of setting 'Normalize Volume' to off and made sure streaming was set to 'Extreme Quality', then restarted and it seems to have worked. After making those changes, I compared the volume with Amazon Music and local files on the phone and it seems fine. I'll continue validate, thanks for the suggestion.
I looked up on Google "spotify low volume" and got to this thread.
The option in the advanced prefrences "set the same volume level for all songs" does absolutely nothing. I notice no difference in volume level except for the fact that it is VERY quiet. I'm not sure if this was a problem before, as I've only recently noticed it.
It's obvious that EVERYONE is experiencing the same issues. Seems the developers are trying to give us the runaround by asking operating system, device, etc...etc...
I am subscribed to premium, love the sound quality, and the syncing ability between PC, Android and Chromecast.
However seeing how obvious it is that Spotify does nothing to help it's customers, is very disappointing.
I'm about to download TIDAL and start a free trial. Hoping it's better than Spotify.
To Spotify: You will end up losing customers over your inability to simply reply to them even to say "we are looking into it, be patient". By being silent you only reinforce the opinion of people that you do not care what they think or what their issues are.