The Anima grind is not the problem.

[Alahra]

I wasted my zeta for a piece of gear that is worse than the standard esoteric weapon stat-wise?

It's actually not. It is very slightly better due to how poor Skill Speed is for NIN, at least going by Dervy's last updated stat weights. Since Kannagi has Determination as the "high" stat and Skill Speed as the "low" one, whereas Yukimitsu has Crit Rate low and Skill Speed high, it very slightly edges it out in Effective DEX.

Kannagi is not, however, better than the Thordan EX daggers despite the higher item level.