Stargate SG-1 was maybe optimistic sci-fi.
Actually it was settled in the present but it was full of good human vibes and human values.
It had an incredible vibe of “humanity is good and humanity will stand against anything bad”. It was really naive in how it described the human nature but I’m sure it was deliberate.
And also it was fun.
That was 20 years ago (1997–2006) (sorry), Eureka was a little more recent and very optimistic (2006 - 2012), the new star treks are recent but they have lost their optimism, I'm not really sure what they are.