T-Mobile Home Internet Can't Access Certain Sites/Cloud Services

It's not just that the site/service is using AWS, it's that it's using IPv4 and AWS. The IPv4 routing is messed up. If I go to 'amazon.com' the DNS will resolve that to an IPv4 address, and that times out. If I go to 'www.amazon.com' the DNS resolves it to an IPv6 address and the connection succeeds. If I disable IPv6 on my PC's network adapter and go to 'www.amazon.com' it will connect, but it will be a lot slower and have pretty high packet loss.