To the person who’ve struggled with Raven, maybe this video would help. Sorry for Japanese, I live in Japan and stream for inner audience. Raven was the second favorite boss for me – right after Naytiba. And the fight was MUCH better and enjoyable than the last boss.

u/JennyJezebel My setup was

Reflex-Type Exospine for easier parry/dodge
Supression-Type Exospine to increase down duration and damage to downed

Beta Charge gear 8%
Beta Charge Gear 19%
Burst Charge Gear 27%
Attack Speed 15%

The main problem with Raven – you can hit her that much with normal attacks while she is down (due to her frame being too small I guess), so you have to use strong attacks combo and yet not all attacks would land every time.
Basically you should try to focus on parrying those attacks you feel comfortable to parry consistently and dodge that one you are having hard time parrying. Meanwhile just take her down with L1 + O every time you have enough beta energy, also you can counter the most annoying attacks with you burst while melting her stance as well with it.

Oh, and every time after the red combo attack she is wide open for the full charged L1 + O. You can down her for as many times you want as long as you have beta energy (thankfully L1 + O hits here fine while she is downed)

Hope that helps! Raven is very nice boss, way better than the last one…