No, the book applies to all programming languages or hosting platforms. That said, the exercises and examples use Go and AWS, because we had to pick something.
Benefits of Go is it's very easy to read for anyone doing Python,
Java, C, Rust, C++ etc. It's a nice middle-ground that's not too opinionated. It's also the language I use most.
AWS is an industry standard right now, and while Azure and GCP are catching up and bringing in very interesting new features, they aren't as widespread as AWS. I also tried to address the self-hosting/datacenter case as much as possible, and worked with people who run their own infrastructure to make sure the advice are applicable, but it's hard to provide a simple lab environment that's self-hosted, whereas AWS free tier fits the bill nicely.