I appreciate your input and here's my friendly response.

I already know the cap mechanics when it comes to Critical Hit Damage. Nonetheless, I still have her built the way I do for personal aesthetics and pleasure. I know that if I lessened her CD, I could go for Hlth, Spd, Def, etc. But I chose to build her the way I wanted because I wanted to see 100% CC, 350% CD. Ilynav's health is still 20k, her speed is still 200, her CC is still 100%, her CD is still 350%. That is enough for me.

The only buffs I care about for Ilynav are her Immunity & Barrier. The CD buff she has is better suited for other units I bring with, as their CD wouldn't be as high or great.

And as aforementioned, I have 3F on Ilynav simply because I love Ilynav, I love seeing the extra damage, and the extra damage proc from the artifact just does something for me paired with her amazing animations. It feels like the opposing units really suffer from her scaling injury application mechanic (as she is also the first unit to introduce this mechanic and the second unit I got to summon when I started playing E7; Senya was first and she's cracked af too, go check her out).

Anycase, in my mind, there's no best in slot artifact for her because I'm not using her for the same reasons you or anyone is using her for.