To be completely honest, if you join Korean as an FO, the worst case scenario is that you will like the job.
I'm being serious, because unless you want to finish your career as an FO you will have to leave KAL at some point to get command somewhere else.
You put very few hours in the logbook on the 737 fleet.
Also, the transition to widebody is not a good move as you will be bonded.
The FO gig only makes sense for furloughed and unemployed pilots imho.
SM