What I like to do when I’m working with collection proxies, especially when transitioning between different parts of the game (eg menu->game->game over->menu), is to have a main/controller script in a main collection and let that script be the controller and the one loading and unloading collections. The controller script will keep track of which collection proxy that is currently loaded, and when transitioning to a new state in the game it unloads the current collection and loads the new collection. You can see an example of this here: https://github.com/britzl/publicexamples/tree/master/examples/menu_and_game
You could also maybe take a look at this routing library created by forum user @megus.sugem