As someone who lives in Wales and likes #linguistics it bothers me how all the @cwtch promotional and explanatory material mispronounces the word.
The vowel is https://en.wikipedia.org/wiki/Near-close_near-back_rounded_vowel, the vowel in "book", not [ʌ] or whatever sound they are making in the two videos on the front page.
I have never heard a Welsh speaker pronounce it that way.