That was the past, helped by Kubernetes and Docker respective decisions to migrate from Java and Python into Go.
Plenty of them are still Java and .NET based, as the ecosystems counter reacted to Go's adoption hype, and Rust is the new kid on the block specially for cloud native Webassembly projects and eBPF.
WASM is architecture-independent (ARM servers are becoming a thing, for better or worse) and has a lot of investment into sandboxing it performantly (since it also has to run in browsers).
Plenty of them are still Java and .NET based, as the ecosystems counter reacted to Go's adoption hype, and Rust is the new kid on the block specially for cloud native Webassembly projects and eBPF.
Like Helm creators nowadays doing mostly Rust, https://deislabs.io/posts/