When you see how many parsing ambiguity problems there are with YAML you begin to wish for XML. Other modern alternatives include:

https://jsonnet.org/

https://json5.org/

See https://arp242.net/yaml-config.html

XML is verbose as hell but:

- it's unambiguous

- with a proper XSD schema you can leverage validation already during parsing, which means you don't even have to boot your application at all - simply load your configuration in any XML parser and you'll automatically catch errors.