I haven't used any of the Amazon Music gimmes since I found Echo. I still hang with the freebie version of Pandora for my random listening option. they have a good set of things for me, but not everyone.
If you think Amazon has wronged you, you should have been beaten by Apple when they started Apple music (Not the iTunes it started with). I had thousands of songs curated by me and album art and obscure music not avsailable in any online music venue. Some really awesome stuff that Apple, upon signing up to their Apple music service, Started replacing with "the best, Apple Curated, Versions of songs available in any streaming service". Which meant the most current version of a song that was 30 years old and I had been listening to for years on my digital devices as I had ripped them myself (before most digital tunes were made difficult to rip), some were replaced by songs with the same name, but completely different music... Apple Music SUCKS. If you even go to the Apple store to buy tunes you are familiar with from the 80's let's say... the most commonly purchased option has become the only version of many songs... remastered, a version found on a different album, some other crap...
I feel your pain in the Amazon music debacle already and forsee more similarities to the Apple "upgrade" as well. Best you can do really, is get a stand alone MP3 player and either bluetooth it to your Amazon echo devices or a standalone msuci machine... in my humblest of opinion...