I think most teachers agree that union itself isn’t the end goal, it’s more like a gateway.
The idea is that personal healing comes first, then inner union (balancing your own masculine/feminine energies), then physical union, and then mission activation becomes possible. Some sources describe twins as becoming “permanent gateways to higher dimensions” once they achieve that unconditional love state together. I’ve yet to see anyone just turn to dust and vanish, but I guess we don’t really know what that means.
People misuse the different types of connections, and when that doesn’t get them clicks on social media, they just start making their own up. Don’t get too worried about it.