I believe that option is equivalent to this group policy:
https://chromeenterprise.google/policies/#BuiltInDnsClientEnabled
In summary: It controls whether or not Chrome uses its own logic to query DNS. It does not control what DNS servers are used (still uses the configuration from the system resolver), so it doesn't sound like it does what you were hoping.
I don't believe Chrome offers a way to select specific DNS servers except through configuring DNS-over-HTTPS, and I am not familiar with what Cronet offers for changing that configuration.