Amazon works fine.
I suspect they work along the rather practical lines of: if we can snag your data we will but if you want to block our efforts at predation but want to spend out, we are fine with that too.
Amazon absolutely will not refuse your money and they are jolly good at extracting it.
It really is not about attestation etc, I'm afraid. Its all about maximising profitability.
If you use a walled garden friendly device then you will be frisked inappropriately at every opportunity.
Technical protections on your phone aren’t going to stop anything if you’re using apps that sell your data from their servers out the back door.
All other websites are just websites.
Also, I have trouble believing that the App Store and public SDKs went from "not on the roadmap" to "released" in one year. I know it's the popular narrative, but I feel like there must be more to the story. It's plausible that they were being worked on but a final management decision hadn't been made to launch them?