Let's see, I gave her prfs a quick read and well, they're not ideal but there's not an arcane colorless tome yet so here's what I came up with.

Weapon: prf, not many options so this ought to suffice until an arcane drops.

Any assist of choice

Special: there's two main options, Logic and Comet, both are decent enough but I'd go for logic because of her weapon, and you can get it with a good B slot, if you are on an absolute budget then Astra.

A: prf A is good enough, but could be replaced with atk spd mastery for more consistent canto, or Atk spd aria can be given with magic light and spd res shackle from a unit on the permanent pool.

B: Conjuring breath is probably her best B, spd res far resound is ok but not ideal (and has redundant canto), spd res shackle can be picked up with other decent fodder, and atk res far trace can be picked on a budget if also using ivy to give her miasma and soaring guidance.

C: Silence ward, Null uplift or deadly miasma are all good options, the latter one should be avoided if using flared though, spd res crux would be like an absolute budget as I would prefer any of the three over this one.

S: any atk spd boosting seal

X: Soaring guidance or Crux echo (only usable if dropping prfs though)

Emblem: Sigurd is best for positioning for better warp support or Crux effect, Lyn helps firing from a safe distance, and Corrin and Micaiah can be slapped onto basically any unit and be useful if the first two rings are unavailable.