What constraints are needed? I've used DSLs that are almost Python but not quite, I think because they were hermetic and deterministic. Even those ended up being produced dynamically using some higher level config DSL or just regular code. Like once you're doing RPCs, it's general programming language territory (though there are also DSLs that do this, which is cursed).
And yes, I have very bad memories of Kubernetes YAML, also YAML itself.
And yes, I have very bad memories of Kubernetes YAML, also YAML itself.