My 6 year old has one of those 288 electronics projects kits and loves it. My geeky friends were surprised they were still made, we got it from an online toy store called Tedco (they are famous for gyroscopes - which he also loves). It’s started a lot of conversations about how electricity works and we go find YouTube videos or other resources to learn about what he’s interested in.
My advice for OP is to not push too much of what you are interested in (like, hacking in particular), but do your best to foster curiosity by asking and answering questions and looking up whatever they ask that you don’t already know. at this age their brain is like a sponge and they can absorb so much about all subjects, and if they’re interested it will rattle around in their head and they will ask follow up questions about whatever tickles their fancy, maybe days or weeks later.