FYI, you can still dedrm Amazon books. Even ones you buy today.

Edit: Not going to lie, it’s a lot more complicated now. But it actually works for Amazon borrowed books too (i.e. - Libby library books)

You have to use KindleForPC 2.8.0. You download the books you want, then run an app called KFXKeyExtract28 to pull out all the keys.

You have to have DeDRM installed in calibre and point the plugin to the keyfile that gets generated (you only have to do this once)

Then you can import the books into calibre and everything will work as normal.

https://github.com/Satsuoni/DeDRM_tools/discussions/25

Don’t get discouraged, it works, you just have to figure out the right workflow that you’re comfortable with.

Also, I have no idea why they don’t just update the ReadMe, as it seems like this discussion thread is the only actual place this is documented.