Аяка is a pretty straightforward DPS that deals most of her damage from her Взрыв стихии. She has very high scalings on her Взрыв стихии at the cost of it being 80 energy. You will likely need another Крио battery on the team to provide energy for her (Диона, Кэйа, Розария, etc). She has a special dash (like Мона) and after she dashes, she will get a Крио infusion on her Обычная атакаs. Ensure you always have this bonus active to maximise your rotation damage.
Аяка's Заряженная атака, Элементальный навык and Взрыв стихии is able to hit enemies sucked inside Венти's Взрыв стихии.
Her Взрыв стихии also stays in place on frozen enemies and slightly knocks enemies away when they're not frozen.
Circlet main stat will be dependant on your overall stats, depending on your overall stats, one can be better than the other. Since Аяка is able to get a lot of Crit Value from (4) set, ascension passive, and also possibly weapons, Сила атаки% circlets can be competitive to Crit ones, it also has a better drop rate, so don't throw away your good Сила атаки% circlets.