I thought Yolantha when I saw it on the thread title. I don't like it, but I don't think it would be unreasonable. Teachers and friend's parents will always struggle, but they seem to struggle with my dd's name which is straightforward but sounds like another, more common name.
Yes, in many ways it is the English pronunciation which is 'wrong', and your preferred pronunciation is closer to the original Greek. If anyone is snotty to you about 'mispronouncing' it, you could be snotty right back.