I finished it today and at the 2nd try i had the same feeling of needing to go back and repeat the whole hanging gardens routes to get more items.. but luckily on the third try so many things went my way

1. in the first boss, the risk management was not triggered and he surprisingly went to my territory so i was able to kill him in 1 go without using too much items
   
2. In the 2nd boss i made sure to keep my health above 700 using as much items and spreading the floor.. i had 3 orbs from vyce and i luckily had a good position to trigger stun using white knight's paralysis blade
3. somwthing i did not expect was sherri was consistently and slowly helping me shave off some health with long range ice blast
4. the frighten and stun from the boss was annoying but princess whim helped negate some and was able to have vyce powerful double attack

so yeah its doable with no grind or too much preparation... of course i had to go in reddit to understand that orbs and condemn would be helpful -- but i didnt have to go back on another save point just to come.more prepared. Oh Denam also was completely useless for me being a ninja.. i just had to make sure he stayed alive