Create a amazon account with a vpn by selecting USA and refresh and go straight to the books and see if the kindle format for purchase comes. If it doesn’t go to the settings and put a random USA zip code find it on google and a select a random USA city. This will make it work. I did the same and never once had a problem purchasing books all sorts of.
Not sure, but Discord just got banned this year in Russia in October or so. Something about it breaking Russian law with some of the servers’ content. So all occult servers and libraries you get there are out of reach.
I believe the traffic is stopped at ISP (Internet Service Provider) firewalls, rather than by the host based on client IP address, so the data is not getting into the countries network to receive, and a VPN can’t bypass that.