What is the J-pop Royal Road progression?
F–G–Em–Am in C major is the IV–V–iii–vi pattern often called the Royal Road progression in Japan. Its rising bass motion leads into a more bittersweet minor chord, which can create both anticipation and wistfulness on the way to a chorus.
A chord sequence alone does not define a genre or make a song sound original. Audition it with different rhythms, melodies, and sounds to see whether it works for your track.