this will sound troll but im not ...
I'm more impressed you went that many rounds and did that little damage.
That looks, as if nobody in the team would have Warmaster or Giantslayer.
Vastah Nerada, if you want to do more damage at CB, you should really bring your champs to the Minotaur and get masteries for your champs.
The clanquest requires survival. For fulfilling the quest damage output is a minor concern.
Technically you are right, you don't need any damage to fulfill the quest.
But the damageoutput from Giantslayer/Warmaster, combined with either lifesteal gear or a lech debuff, makes it much easier to survive the required number of turns.
^ This
But yeah, I follow up with my regular team and turn in 12mil or so, to qualify for a top chest.
Nice keep at it. Clan boss is one of the best ways to progess your account, chance at shards, books, and the occasional piece of decent gear.
Keep at leveling up champions and maybe watch some videos and hopefully move on to even better top chests.