I know the Mariah Carey song is hated because its overused, but its also objectively a well produced piece of pop music.
My favorite though is O Holy Night. Performed well I want to stop and listen to it. It moves me, and I dont give enough of a fuck about religion to call myself an athiest.
I searched and found this playlist of alternate carols last week.
https://www.youtube.com/playlist?list=PLqAaxjrofZ669u1edytC5otNjn_EWuRVt
A cheerful mix of science, cthuhlu, and athiestic themed carols.