I have never used the app. Like you, by the sound of it, I find Amazon Music user unfriendly and I have little interest in it.
I have, however, purchased many albums from Amazon which came with AutoRip. I find I can still see and access these by going to “My Account” on the Amazon website, then click on “Your Music”. Then there is a “Library” tab at the bottom which enables me to access all of those AutoRip purchases. So, no, for me at least they have not disappeared. I never really listen to them though !
Downloaded and installed the Mac version - thankfully macOS warned it was trying to set it to start automatically on boot as well as trying to run some background tasks I didn’t want it to.
Online amazon help pages suggest there’s a ‘Purchased’ section but there isn’t for this version.
I’m sure I’ve purchased much more over the years but it gave around 200 titles, many of which appear to be AutoRip and a few I purchased years ago. Not all download for some reason, one or two I don’t even recall purchasing.
Appreciate they are MP3s but there may well be some there that are no longer available or can’t be downloaded elsewhere.
This process works but unless I’m doing something incorrectly it shows a long list of tracks and I don’t seem to be able to download by album, unlike with the desktop app which is why I used to prefer it.