I did a walk-up amateur radio workshop with the Girl Scouts at a STEM festival a few months ago. I likewise was very surprised by two things: the younger kids had _no idea_ what they were looking at (isn't the radio in the phones? Spotify?), and they were also completely enamored with the gear. Some of the older kids (14-ish if I had to guess?) spent a lot of time with it.

For the younger (7-10 year old) kids who came to our table, we actually didn't do anything terribly technical - we just asked them, "What's your favorite type of music?", showed them how to tune to an appropriate local FM station, and let them see the waterfall plot of the station, put the big headphones on, and that sort of thing. If any of them showed an interest, I'd hand them a hand-held CB radio, one of the big clunky 80s ones from Stranger Things, and let them make "their own radio station", then showed them how to pick it up like the FM station. We got a lot of younger visitors this way!