> I need an explanation how these implementations are not "cross-platform" yet his Go implementation is. OP here. I agree the wording is a bit unfortunate here

> I need an explanation how these implementations are not "cross-platform" yet his Go implementation is. OP here. I agree the wording is a bit unfortunate here, as all languages mentioned were designed to be cross-platform. I was referring rather to the practical complexity of using the code in different environments - native desktop, mobile (Android/iOS) and Web (JS/WASM). With Go you can take normal Go code and build it for iOS/Android/Web in a few seconds with a minimal effort. I personally don't know if this even possible for Java/Python/JS, let alone with such an ease.