Which pronunciation of “kun” is correct or what’s the difference?
In my opinion, the Chinese pinyin "kun" sounds like "kwen".

If you like to take a further look at the the pronunciation, you can see Zhuyin(Bopomofo), which we often use it in Taiwan: ㄎㄨㄣ

ㄎ / ㄨ / ㄣ

k / wu / en

BTW, I think those two audio sounds familiar.