I pronounce it like
Ivana as in Trump. That's my first and only thought about it, really. Otherwise It just seems like a trendy add on to Eva/Ava/Evelyn. It could be pretty in theory but feels a bit princessy and over the top; like, I'd feel pretentious calling out to my kid named Evanna.
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"We are all horrible and wonderful and figuring it out." - Harris Wittels