Not everything has to be competitive or official either. Like you can just go to the community pool during the summer without joining a swim team. I think some parents forget this, but this was normal for previous generations.
So my kid has a few extra curricular activities and then I also do plenty of activities with them at the house like play chess or card games or whatever. They're also watching some of my old favorite sci-fi shows with me. Nearly all of YouTube kids is steaming garbage designed to turn your kid into a mindless consumer. Netflix kids is pretty good though. There are a lot of shows that have character progression and multi season plot arcs that cover complex subjects. Avatar the Last Airbender is an example of a show I was comfortable with my 7 year old watching without worrying about brain rot. Mind you, I think all screen time needs a limit.
by teaching them that work is good and necessary. There's a book by Neil Postman Amusing Ourselves to Death, the central idea of which is that "form excludes content". The problem with Youtube, or in his time TV, isn't just the content, it's that all content by the nature of the medium must be entertaining. If it isn't entertaining, it isn't content.
Hobbies feel like work because they are like work, because most things worth doing have a component of work to them. Rather than just trying to see what sticks, the best thing you can teach kids these days is that they should stick to the thing and that expecting "fun" at all times is a bad expectation to have.