like the above comments say most sageuks are top notch in terms of production quality. i've recently been trying some but the ones everyone reccomends have like 50 episodes. one even had like 80 or 60. i can't watch that much.

im really enjoying queen in hyun's man right now which is a fantasy time travel romance saguek that's super good and the leads have incredible chemistry (they were actually dating & he confessed his love at the press conference)