Routes in Codeigniter
Have a look at https://www.codeigniter.com/user_guide/general/routing.html.
$route['user(:num)'] = "users/profile/user/$1";If you mean you want /anyusername to route to the users controller, you would have to put:
$route['(:any)'] = "users/profile/$1";At the bottom of routes.php and every non user-URL above it. Otherwise every URL would be routed there, obviously. You will need to implement some mechanism in the users-controller to throw 404-errors, since you are routing all requests not catched in the routing rules above.
IN config/routes.php
add this line
$route['user(:num)'] = "users/profile/$1";