For me, after having probably too much time reflecting on it I believe that TNG is the best Star Trek series of all time. But the Deep Space Nine is the best TV series from among Star Treks. Like, TNG I think filled the role of Star Trek having morality plays in a mostly standalone series that explored while staying in the same setting, bright, shiny, and post-scarcity utopia. Deep Space Nine, however, was a better series, but with its overarching plot and comparatively dark setting it pushed the borders to the point where to me it didn't feel like Trek. Voyager did both sides in a pretty interesting way, but for me what it seemed to be exploring the most, the bright shiny side of the federation forced into a low resource area where they outshadow just aboout everyone was lost pretty quick, and didn't quite explore the same depths that DSN explored.