btw there’s a build in the game that can deal 100k DPS, but only for a couple of seconds
It might have to do with the bone shard item getting multiplied by damage bonuses, but the build I'm referring to is cinderblock fish and snails (potential 2025% damage bonus).
(I haven't been able to even get close to an all level 3 run, though, so I think it might be balanced by the rng requirements)
Edit: just tested it; the bones are definitely benefiting from the snails' damage bonuses (when I killed the tentacles, the dps shot up to 85k)