Technically, the eye icon in a scene's list of sources, turns that source on or off, so you could "stack them up" with each one hiding the ones below it, and use those to switch. But why would you do that? It's not how OBS is supposed to work, so a lot of the features...won't.
And you may have to switch to that scene again to make it show live, as those eye icons are technically edits. You normally don't show edits live, but finish them and then explicitly show the result.
Far better to have a dedicated scene for each thing that you want to show:
- Different camera? Different scene.
- Different overlay on the same camera? Different scene.
- Pre-produced video instead of a camera? Different scene.
- Different video? Different scene.
- Etc.
So you have lots of scenes with relatively few things in each scene, and you switch scenes a lot. That's how OBS is supposed to work.
What does that mean?