What is the feature or ability you would like to have? Amazon music available on the standalone SC6000s like Beatport and SoundCloud is.
Is this feature for OS, Desktop software, or both? Both.
How will this feature help you and others? It will help me and others have more music available that I can not access on Beatport, SoundCloud or tidal.
Is this feature available in an existing product? If so, what product? Prime 2 and 4
Does a workaround currently exist?
Not for the SC6000
I’ve changed this “request” to a question as it cannot be implemented.
The required hardware isn’t in the unit to support Amazon Music.
The sc5000/6000 do not have the Amazon chip built into them so will not have Amazon music enabled. The Prime 4+ is currently the only hardware with the chip inside
And the Numark Mixstream Pro+ and Pro Go
Good catch, thanks @Reese
Same reason Amazon got rid of the comments and blogs: Bezos is a jerk.
And Denon DJ SC LIVE 2 & Denon DJ SC LIVE 4 
Is it really the case that Amazon Music has a larger library than Tidal or SoundCloud (as claimed by OP)?
[edit] Just checked. Amazon = 100 million. Tidal = over 100 milllion. SoundCloud = 135+ million.
I don’t understand why it didn’t occur to the development team to make a USB extension “dongle” which would embed the Amazon DRM chip and which could be sold as an option for users wishing to activate Amazon on older units that do not support it.
I think the units have enough USB ports and that allocating one to a USB dongle of this type would not be a big sacrifice. Engine OS would only have to check the presence of the USB dongle to activate the service on the unit.
It all depends what Amazon’s terms and conditions stipulate.
Interesting, not to mention you could also use an extension. Heck, an Amazon dongle could have a built-in extension or USB port pass-through. Plug it in the front and it’s a little rigid or corded extension. Having little passive, corded extensions into at least the front USB isn’t actually a bad idea, anyway, because it prevents scratches and reduces the likelihood of the USB port on the unit breaking down.
Though I might be nervous about someone stealing a dongle on the front. Might be better to use a rigid dongle with a pass through on one of the rear ports, maybe even with a little kensington lock cable on it.