Is it possible to remove Route objects from a RouteCollection object? When I look at the code used for the method handling a RoutingEvents::DYNAMIC event, which receives a RouteBuildEvent object, I notice the code is always similar to the following one.

$collection = $event-&gt;getRouteCollection();
$route = new Route("$path/display", array('_form' =&gt; '\Drupal\field_ui\DisplayOverview') + $defaults, array('_permission' =&gt; 'administer ' . $entity_type . ' display'));
$collection-&gt;add("field_ui.display_overview.$entity_type", $route);


Since the RouteCollection class defines the RouteCollection::remove() method, would not removing routes from the collection be possible? I was thinking of removing a route to redefine it.
There is also a RoutingEvents::ALTER event, which runs afterward.

You can think of the difference between RoutingEvents::DYNAMIC and RoutingEvents::ALTER as similar to the difference between hook_menu() and hook_menu_alter().

There is a Views issue that discusses replacing routes, as opposed to removing and adding them, perhaps follow their example.