I wanted to try using yamlpath (yaml-set in particular) to recreate the first example, even though the usage model doesn’t quite match up. It’s a bit tedious because I don’t think you can do unrelated replacements in a single command:

$ <<<'{}' yaml-set -g ignored.hello -a world | yaml-set -g tabwidth -a 2 -F dquote | yaml-set -g trailingComma -a all | yaml-set -g singleQuote -a true -F dquote | yaml-set -g semi -a true -F dquote | yaml-set -g printwidth -a 120 -F dquote | yaml-get -p .

Trying to make it neater with Zsh and (forbidden) use of eval:

$ reps=(ignored.hello world tabwidth 2 trailingComma all singleQuote true semi true printwidth 120) cmd=()
$ for k v ( ${(kv)reps} )  cmd+=(yaml-set -g $k -a $v -F dquote \|)
$ <<<'{}' eval $cmd yaml-get -p .