How can I change the default browserWindow Close Timeout (e.g. from 2000 to 5000ms) in keyword test

There's a keyword test example in Close Web Browsers

Either create a script to close the browser window, and then call this script within your keyword tests. Or you could implement TestComplete Events such as OnStopTest Event

There's no general settings, you have to implement the code, which gives you more control as to what to do after tests finishes.