The Rust of today wouldn't be chosen over the Go of a decade ago, it is fundamentally a bad fit, for similar reasons that the already mature C++ wasn't. Java (similar to C#) would've been viable mainly due to maturity and ecosystem effects, Kotlin/Native might be a contender in another half decade, sooner if the team were to shift priorities.
I say this not just for Kubernetes etc., but greenfield projects today as well.
Let's just entertain the idea and pretend that this is a notable project and that one would count it as DevOps tooling.
Here are the top 10 across the CNCF in terms of size, courtesy of GitHub's API:
I say this not just for Kubernetes etc., but greenfield projects today as well.