I'd throw everything at them and see what sticks. Try web, gaming, hardware, ML, puzzles... find a place of passion and grow out from there. Try to give them a tour of what can be done in each domain, and see what they'd like to try.
I'd do the opposite. I'd find out which of those things interests them, and then guide them strongly towards a popular solution for it. If they change their mind, that's fine. But too much choice can make it really hard to approach.
Have you not heard of the idiom "see what sticks."? What you described is not the opposite - its actually the same :) See what stays with them naturally and them go with that.