I like it but I pronounce it RAH-ya. It's my favorite spelling also so you didn't come up with it ;)
Rhea I pronounce REE-ah or REH-ah.
Raya I pronounce RAY-ah. If you want to go with RAY-ah I'd spell it
Raya it would make things easier.
I don't think it's made up, just a spelling variant. I like
Laia but it's too close to Raia. I also like
Leia.
I like
Ariadne.
Aria is pretty close to Raia, though so I'd only use the full name. Prefer
Ariana, though.