Transfer 500K points

Not going to be traveling domestically as much, retiring, so think I'm going to cancel my platinum ( they just offered me 200k for a business card tho).

I never use the lounges and never rent a car or Uber eats.

I will be travelling locally (by car) and am a Mariott Bonvoy member.

Would I be better off transferring to Mariott or Korean Air, which I will fly 2x to 3x a year? Looks like to me I really get hammered on Korean Air?

I will not be staying at any Mariotts in Asia.

Just hoping others may have faced a similar situation.

TIA