Y’all

I've been reading it as the first version but now I'm confused

idk how to either but i pronounce it as “hiyo-unh”

Hiyo-u-nh

its Hyo-oon

Hyo is one syllable so it’s more likely to sound like “hiyo” if you slur the “iy” part of it. Un is also one syllable so it’s unh. You say it as you would un but push a little more air through when you say it. You wouldn’t split it up as slowly as you would in English when saying hyo-un and instead would say it as if it is 2 syllables of one word. This is how I learnt to say words in Korean but tbh if you want to learn properly, you need to learn the pronunciation of the Hangul letters because to tell the truth, all romanisations will be slightly off as they use different mouth positions than we do. L and r are separate in English and have different mouth and tongue positiosn whereas in Korean ㄹ has a mouth and tongue position halfway between l and r so romanisation could be either/or depending on what seems better and more easier to comprehend.