I see two very prominent thoughts on what nmixx should do in terms of songs and concept.
1. Keep what they have
2. Go to twice's old sound
For keeping what they have, nmixx would be so hyped if their song was just decent atleast. The girls are so insanely talented and pretty and the only reason they're not is because of the concept they have right now. For going back to twices old sound, I love twices old sound esp knock knock, cheer up, and likey but that would be a complete waste of nmixxs talent. Have you not seen how those girls perform on every stage? They're such strong powerful performers and literally even their performances in that random thing on the beach could eat up a lot of the other 4th gen ggs.
Personally I think they should pursue something like blackpinks boombayah. It would allow them to keep their strong stage presence and dancing while giving them the sound that they need to succeed.