It's interesting that AWS chose(?) not to support this. Can you think of any reason why they wouldn't have? Perhaps it's harder to predict use cases in C++?
I don't know exactly why AWS didn't include C++ SDK when they announced all languages are supported. Maybe it's more common today to use Java/Rust/Python to build data products, but C++ is still such a solid case. Anyway, I will try to reach out AWS team to see whether they are open to put this into the AWS SDK for C++