I have never heard fsck pronounced as other than "fisk". I reckon the variation in pronunciation is due to a mainly written communication culture.
"Did you try to fuck your filesystem?"
"It's fucked already!"
"No, just fuck it; that'll unfuck it"
On the pronunciation of “fsck” - https://news.ycombinator.com/item?id=38672435 - Dec 2023 (66 comments)
One day, he said something like, "I was myzulled!", so I said... "do.. do you mean 'misled?'" at which point the light bulb moment occurred, and afterwards, we continued to deliberately use the "myzulled" mispronunciation as an inside joke.