Resolve CORS issue without changing services.yml file
Can I achieve w/o enabling cors config?


No. Without CORS configured, the server and browser will correctly conspire to reject the request.

You could implement it yourself, rather than using services.yml, but something needs to set the headers. And at the point where all you need to do is make a few simple edits to a configuration file, I'd question why you would want to write all that extra code yourself.