My instance is @lemmy.world, so this community/post is "local" to my instance, but in practice that's not super important.
I think that's generally true, however it's worth noting that what you can see from other (non-local) instances is dependent on the admin of your instance. They choose with other instances to federate (exchange data, e.g. communities, posts, comments, etc) with. If they choose not to federate with a specific instance, you won't see content from that instance.
There are already examples of this, but I don't know the details well enough to be confident in expanding on it.