Do I need to manually load each asset from an asset bundle or can it happen automatically?

Im attempting to integrate asset bundle usage into our existing game and im a bit confused as to how asset bundles would typically be used.

Most of the tutorials i’ve seen regarding asset bundles showcase specifically instantiating objects that are in a bundle from code however this seems like it would be incredibly difficult to integrate into an existing project.

Is it possible to package all the textures in a scene for example, and have those textures be all automatically loaded and their references assigned without having to put a script on every object that will use those textures?

You can bake the whole scene into the Asset bundle and then just use - Activate Scene (additively), this will load the scene from the bundle (make sure to load the bundle into the memory by new UnityWebRequest (previously was done with WWW) ).
It will load all of the Texture, References (you cannot add scripts into the Asset Bundle but the component swill link to the referenced scripts and the serialization will do its job).