WordPress REST endpoint not able to reach with jQuery

First, lets fix your endpoint:

function wpc_ylp_rest_videos( ) {
  $myObj->name = "John";
  $myObj->age = 30;
  $myObj->city = "New York";
  $myJSON = json_encode($myObj);
  echo $myJSON;
}

There are a few problems here:

• callbacks for REST API endpoints are meant to return their data, like shortcodes. The REST API does the JSON encoding, you’re not meant to echo
• $myObj appears to have been summoned out of nowhere, this will generate a large amount of PHP notices and errors. Never do this, PHP will have to fill in the gaps, and relying on computer to “get what you meant” rarely works out
• There’s actually a first parameter given to you that lets you read in parameters instead of using $_GET or $_POST, that allows you to use a lot of the features

It would be much better like this:

function wpc_ylp_rest_videos( $request ) {
    return [
        'name' => 'John',
        'age'  => 30,
        'city' => 'New York',
    ];
}

Second, I tested your AJAX request code with this:

jQuery.get( '/wp-json/wp/v2/posts/', function( data ) {
  console.log( 'DATA',data )
});

The result worked as desired