It might only take one angel to fill an entire black hole if God so permits or requires. However, I think angels have more important missions in Heaven and on earth. Consider the work of guardian angels. Some saints had the gift of being able to speak to their guardian angel. And just because an angel appears looking like a man, like in the Old Testament, only means they took on that form for the benefit of the humans they interact with.
One example is Tobias wrestling with the archangel Raphael, which symbolizes his “wrestling” with God. We may see ourselves in Tobias on various occasions in our lives. Then there are the angels who looked like young men at the home of Lot and his wife.who protected him from the evil townsmen, the angel who saved Hagar and her child, stayed Abraham’s hand from killing Issac.
In the New Testament, we know the angel Gabriel gave the message to Zachary that Elizabeth would have a child and, of course, to the Blessed Mother. They sang “Gloria” to the shepherds at the birth of the Savior. An angel comforted Our Lord in the Garden of Gethsemane.
At Fatima, the three children first saw the angel of Portugal and received Holy Communion from him before the apparitions of the Blessed Virgin. So there are angels in charge of each country. (If a country splits into factions, I wonder if stand-by angels would be requires. Hmmm. . .)
Sorry about going off on a tangent here, but I just thought I’d pin the debate on more significant issues (pun intended

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