I always liked
Kaia but lately the C spellings have appealed to me. I fear that Chaia will cause pronunciation problems so it's between
Kaia and Caia. I like Caia because it looks like a feminine version of
Caius but I don't want to be trendy.
So yeah
Kaia or Caia?
or Chaia,
Kaja, Kaya, Caya,
Chaya? what is your preferred spelling?