Rather than focusing on which application to make, maybe it would be a good idea to more fully research the other end of the equation - how to redeem.

You're looking for a relatively difficult ticket to find - smaller US airport on the wrong side of the country to Korea. If you accumulate UR points, where will you transfer them? Does that program typically have availability when you want it?

An Arrival signup will earn you around $500. Can you find a retail ticket where that little of a credit makes sense?

We have forums for all the major programs here with threads that discuss strategies on actually finding and booking tickets. The booking strategy should dictate which cards you apply for.