Conjure Celestial (Cleric 2024, 7th level spell) is incredibly powerful

We just transitioned our characters from 2014 to 2024, and in doing so I decided to prep the new spell Conjure Celestial because it seemed VERY strong (and my cleric has warcaster and 26 AC, so he holds his spells very well).

We had a deadly rated encounter over the weekend. Lots of Death Sloads, a green sload, a custom boss with legendary actions, and a number of minions.

My wife's squishy sorcerer was grappled by the boss with telekinesis. One round of multi attacks took almost 70 HP and had her in the teens. I dropped Conjure Celestial and hit 2 death sloads, the green sload, the boss, and my wife.

In that one round, my spell did a total of 24d12 of damage (6d12 per enemy) plus 4d12 of healing to my wife. She teleported away and I moved the light onto her and a few cannon fodder enemies the next round - healed her UP TO FULL.

They were trying to break my concentration but couldn't. In that one fight I think I ended up doing over 400 damage with that one spell, and over 100hp of healing. I kept concentration the entire fight and actually CHOSE to drop the spell when we changed to a lower level of the map.

This spell is an encounter-breaker if you hold concentration.