My surname is Cuch. Though I don't know much about Polish, I assume that this derives from the Polish word for chain, łańcuch. I pronounce my name as I've been briefly told by relatives: /tsux/ in the IPA for Polish. However, online I read many sentiments to the effect that [x] is "also (in great majority of dialects) represented by ⟨h⟩", which would yield a great difference in pronunciation.
I only need to go to the IPA for Polish Wikipedia page to be told a bunch of perfectly valid information but which makes no sense to a beginner like me, such as:
"All voiced obstruents /b, d, ɡ, v, z, ʐ, ʑ, dʐ, dʑ/ are devoiced (so /d/ becomes [t], etc.) at the ends of words and in clusters ending in any unvoiced obstruents..."
I don't know much Polish vocab, but I've heard my father speak a lot to other relatives and in words like chleb and łańcuch his pronunciation seems to reflect [x] more than ⟨h⟩. However, perhaps modern Polish leans more towards ⟨h⟩.
My father's side of the family on the whole do not like to discuss the specifics of Polish or Poland much due to having seen a lot during the war. Hopefully posting here will give me a better idea.