Not knowing where you are, it’s hard to say. But you might as well start with whatever is most accessible to you. Getting involved will help you get to know who’s doing what and how in your area. I will say it’s usually easier to move from less to more radical groups than the other way around, so if you’re shopping around, you might want to start with a more mainstream group.

It’s entirely possible this is just attentional bias on your part. You noticed the more vibrant, active adults when you were younger because they were more interesting to you.

But generally, things are worse these days, too. I feel like people used to talk about the future optimistically when I was growing up. Maybe people still talk to kids that way now, but I don’t. And I don’t hear people doing it. So, maybe you’re on to something here.