Telegram doesn't rely on Amazon or any other third-party cloud service. We have built our own secure cloud infrastructure, distributed across the globe. It took us a few years to create the technology to instantly sync encrypted data between our datacenters and to encrypt local storage in each of them in a way that would make breaking into any data-center and seizing servers useless. The encryption keys used to secure the Telegram Cloud are split in pieces and never stored in the same place as the information they protect.

As a result, our approach is more advanced and secure than what Amazon or any of these general purpose cloud services can offer. And since we run our own infrastructure, providers like Amazon can't block us.

Besides, we have no illusions about Amazon in particular. When Russia banned Telegram in 2018 (more about it here https://t.me/durov/80) we set up independent proxy-servers on Amazon's AWS to allow our Russian users to freely communicate on Telegram. Amazon was pretty quick to deny us access to their services. Back then Amazon managers told us they had to do it to defend their business, but as a result they also defended censorship. Other providers such as Digital Ocean were much more helpful when it came to setting up proxy servers to defend freedoms in Russia and other places.