Speaking as someone who was only able to embrace a love of music after no longer being forced to take piano lessons: she's got the basic ground in musicianship already, yes it is unreasonable to keep making her take music classes if she does not like them, and LW is probably thinking too much about their own musical regrets.

End the piano lessons, do not sign up Daughter for voice lessons unless she volunteers the idea, and in general let her pick her own level of engagement with music. Also cosigning the idea that it isn't too later for LW to pick up a musical instrument again.