It’s “puh kahn,” everything else is something best used in private.
Exactly correct...I’m seventy plus and knew my grandmother who was born in the last year of the War for Southern Independence and she pronounced it “puh kahn” which says to me that it is likely her ancestors all the way back to their arrival in Charleston in 1696 pronounced it the same way. Now Yankees may pronounce it differently but, hey, those trees don’t grow up there so they are entitled to be incorrect.