Ask HN: Which passive income streams would you recommend for a web developer?

I am a software developer for many years now. I want to do more projects for my own than for somebody else, and get out of a day-to-day job.

Of course, as a developer, there are many possibilities. I am a web developer, so the whole App ecosystem is not my favourite, but I could learn Swift etc. if needed.

The question is: What is your experience in creating a passive income? Which direction did you follow? Is it still worth investing time in an iOS App when you just have the weekends for the beginning?

Happy to get some insights.