Very specifically: what artist sings the final song (through the credits, ep 16? I can't find it on YT, but I'm also not literate in Korean...

Full OST on spotify is here: https://open.spotify.com/playlist/5sRnsdzKk9UYkYP4ymDa3P?si=0403e4e18b654885

The song in the credits in ep 16 is LOVE CODE [1+1=1] sung by Vincent Blue. 

You're the best!  Thank you!