isForceCreate = String(data.callingMessage.forceCreate) == "true";
isNewUser = String(data.message.newUser) == "true";

var response = {};
response.status = 200;
response.data = data.message;

if (isForceCreate && isNewUser) {

    var min = 10000000,
    max = 999999999
    prefix = ["player", "user", "member"]
    
    const num = Math.floor(Math.random() * (max - min + 1)) + min;
    const pre = prefix[Math.floor(Math.random() * prefix.length)];
    
    var defaultPlayerName = pre + String(num);

    var playerStateProxy = bridge.getPlayerStateServiceProxy();
    // We are changing the player name on the server.
    playerStateProxy.updatePlayerName(defaultPlayerName);
    // And in this API Call's return data.
    response.data.playerName = pre + String(num);
}

response; //return the object

This works just the way I need