Here is my experience:

I purchased a trans-pacific business class flight directly from KE in October for a January 1 departure. I was advised when I booked the flight that seats could not be assigned until 30 days before departure. I then forgot to call KE at the beginning of the 30 day window...it was more like 24 days from departure.

My call was answered by a friendly lady who assigned seats I wanted. She also assigned seats for the return trip, even though that don't flight departs more than 30 days from the date the seats were assigned.

At the end of the day this is just another flight in a metal tube across an ocean. Korean Air will get you to your destination safely and comfortably. You/we are flying an Asian airline ....adapt to the carrier's culture and enjoy the flight.