There are few ways to beat the second boss and in this guide you can see some of it.
Guide to Kill Second Boss
Simple but long-drawn-out
Go to bottom right or bottom left to hide skill.a little of healsteal is emough. The higher dmg, the better. The monsters after have a lot of hp.
Hug the far side of either wall but do not stay in the top right/left corners – Head down about 15-20%. You do not need to change sides for one hand or the other and can wall hug all the way until the death of the hand you’re close to before moving to the other side.
Re: Healing – Leech/Sustain is mostly a trap since you get full hp + gourds replenished after each major boss going into new areas and damage scaling is insane with the right items.
Try to keep enough health to get to the merchant without using any gourds and spend some cash to heal if you need it so that you have full gourds for the area bosses.
Also you can take 1 object or skill of healing or shild (enough), therefore,we can choose the room of soul instead of healing room.
You need to hit one of the hands a bit, then move to the center and fish for a swipe, then go back again to the same hand. They’re pretty easy to avoid if you time it well from the center.
Staying all the way back is viable too, but will take far too long relying just on ranged attacks.
In the boss arena you can dash to lower middle left side to avoid being swiped.
So assuming the red is the boss and his 2 hands, then the blue circles is roughly where you want to dash to.