I believe you think that DIS is the most optimistic because of its emphasis on emotional depth.
And I guess we can agree that the part of ambitiousness is a default of startrek for as long as it involves creatures from all kinds of worlds building teams and manage to work together. Basically for as long as the federation aka starfleet is part of the story.
Then why is it not a problem if that ambitiousness is paired with "optimism" ?
What I'm trying to say is: nobody is forcing you to do a job that you hate. Nobody except the internalized worldview that you are only human if you can proof a professional career.
Maybe it's just the dis affectionate aspects of humans that I'm projecting..