Dmg on ulti without pcr

Hi guys, i dont have a proto clarity rose sword from the event, and im thinking about how much difference (need some numbers) would it make if i use a mid budget sword like 4th anniv sword ix (1s any xtal) +b refine for example or something along those lines against a boss on ultimate difficulty like venena (300*6 = 1800 def, if im not mistaken). Would appreciate if anyone could try that or tell me your experience with that <3

 

Numbers hurts my brain

 

if she has 1800def, your atk is reduced by 1800 before damage calculation if you don't have physical pierce.