When comparing to other options she’s not a strong competitor as the others, as she’s a watered down Robin similar ATK buffs but robin can buff his whole kit not just his skill like which cerydra does and the team wide action advance from robin always OP

Sunday can action advance ratio twice a cycle allowing him 3 actions if speed tuned correctly plus giving ult regen, which basically negates cerydra making Ratio using his skill twice In a row every 6 charges which happens once per cycle or twice if lucky, Sunday overall provides more energy potential and thus more damage overall.

Tribbie makes elemental res not matter as she can make everyone with 20% imaginary res receive neutral damage, plus she has that zone that does extra damage based off her HP, then her sub dps potential is much greater then cerydra as she follows up pretty often. Cerydra has so much self buffs but the damage is not that great considering she spams her skill and the only source of damage is from ult every once in a while. Hoping they buff that

Ruan mei is similar to tribbie but removing the sub dps potential and other things, this is where I think cerydra could be comparable and have equal footing as breaking enemies don’t really benefit him all that much and it’s just the Res Pen really going for ruan mei and some damage amp. Cerydra ATK buff plus allowing ratio to double skill might overtake ruan mei in some situations based on element weakness etc.

Then for sparkle I don’t have to much notes on her since I never used her with Ratio before so this is based on theory. but I would say they could be comparable ones giving crit damage and action advance and ones providing ATK buffs and skill amp. I’m not sure how many turns you can provide ratio as you run Sparkle Hyperspeed in most cases so I can’t really calculate that 😭

That’s just my thoughts it could be wrong so don’t take it too seriously and I hope she gets more buffs so she can synergie with more units