I'm not an expert but, E=MC², so take the weight what they're moving around, multiply it by the speed of light squared, that's the amount of joules of energy you have, assuming perfect conversion.

It doesn't say how much material they moved though. If it was exactly 1 gram and they cancelled each other out perfectly (according to a quora answer, I refuse to trust AI but a random internet commenter is fine lmao), you've got 2 grams of mass converted to energy which is 180 terajoules or about 43 kilotons, which is about equivalent to 3 Hiroshima bombs.

Punching that into https://nuclearsecrecy.com/nukemap/ gives a blast radius (of window destroying power) of 5.79 kilometers, or just over 100 km² of affected area.