Lorule is quite clearly shown to be the inverse of Hyrule, but Hyrule contains the main universe, and Lorule, being its inverse, has the same size. To further prove this point, Lorule even has its own Sacred Realm, separated from Hyrule (universe).
The scale of the destruction is universal. First of all, as the image shows, Lorule is the name of the universe, while the kingdom is named "the kingdom of Lorule" to differentiate them. Hilda states: "Let's talk about this country for a bit. Long ago, there was a triangle that if touched, grants any wishes in Lorule. It's called Triforce. People fought over for this power, resulting in kingdom's collapse. The kingdom of Lorule, to stop this, destroyed the Triforce. But it backfired..... Triforce is a power of God. It's existence is the pillar of the world, holding it. With Lorule, not having the pillar, is destined to collapse. This land needs Triforce. One day, We knew the existence of the another world's Triforce. Triforce of power, wisdom and courage. Your mission is to wake up the Triforce of courage. I need to correct the mistakes of my predecessors as a queen of this country."
Look at how the terms are used. First she says that the Triforce was in Lorule, which makes sense given that it was in the Sacred Realm and not in the kingdom. Then she states that the wars caused the kingdom's collapse, which is true given that the effects of the war were felt only in the kingdom. She's very consistent with the distinction "kingdom" "Lorule". So when she says that "Lorule is destined to collapse" she quite clearly meant Lorule as in the universe, as stated by the image above. And before you say it, "world" (or Sekai in Japanese) CAN mean universe, despite how much this wiki tries to go against it. It's NOT the only meaning nor the most common one, but it can mean that with enough proof and this is the case here with its connection to the word Lorule. Especially given that it caused the destruction of the Sacred Realm as well.
Is this enough or do I need to bring up more?
@Rein kind of
So it still mantains the 3-A sense? I'm unsure now.