I would rather read K8s manifests in yaml than any of the alternatives. The important point here is that config/serialization languages are like programming lan

I would rather read K8s manifests in yaml than any of the alternatives. The important point here is that config/serialization languages are like programming languages in one key aspect - there is no single language/format that covers every need. The choice is based on the tradeoffs - there are cases where yaml is better than toml and cases where the inverse is true. There are also a lot of cases where people prefer a bit more features like Turing completeness (eg. jsonnet. Ansible playbook format is a counter-case where yaml gets retrofitted with ill fitting features). And there are cases where such features don't really make sense (like serialization of state in K8s). It's not like anyone if forcing you to use one format. For example, K8s spec can be in yaml, json or jsonnet. Choose what feels most natural, instead of sticking with the default and complaining. Conversion between formats is cheap anyway.