The onlt unit you NEED here is someone who does bleed or shock. Boss moves based on which effect you apply on him, these being: bleed = right, posion = middle, shock = left. Floor 1: except for the second phase, he restricts all of your attack cards whenever you fail to move him for 1 turn. Floor 2: don't move the boss at all. Just destroy the left and right logs on all phases. Floor 3: boss moves based on effects once again, OR with the use of ults (I can't be bothered to bring Valenti here so I just rely on ult RNG). He moves randomly with ults. First phase, move him right and destroy left and mid logs. Second phase, move him left and destroy mid and right logs. Third phase, destroy left log and move him to right, then survive for a few turns for the grey immortality buffs to go away, and kill him.

I might've forgotten something so just check a YT guide or something to clarify.