I don't see Star Trek through the same lenses you do. It had a vision of a future that is bright. Most people today like to look at the future with very dark lenses due to current events and what not. Their choice, but it's not how I like to look at things if I can help it.
Star Trek is far from being a children's story - it had some really really great episodes that even as an adult wow me (DS9 included) - the coherency from TOS to TNG to DS9 to VOY is admirable across all those TV shows. That's a feat you don't see much of (over that timespan).
I'm glad you're finding things to enjoy as you get older - I count Star Trek as one of the things I enjoy - minus the last 5+ years (I can't enjoy most of whatever that is called). It's interesting - a lot of the 80s shows I grew up with are more enjoyable to watch than a lot of the CGI camera shaking swinging no storyline crap they throw at you today lol.
As far as reading books, my drug of choice has always been non-fiction history - will never get enough.