So what happens if 2 black holes collide full on at the near speed of light

I theorize matter ejection, a plasma bubble, rapid expansion, cooling condensing and gravitational hotspots, the matter would attract and try to re form a single structure the gravity of the 2 black holes now spread across a universe which is fighting to hold together while the initial explosive expansion tries to spread everything outwards.

Heavier metals could have been present in the initial plasma release could they not? Without some difference in the density of the cooling plasma there would be no irregularities in the universe, everything should be the same, just an endless dissipation of energy