Your denigration of real estate and stocks doesn't make much sense.

If you have the capital to buy rental real estate (admittedly a big "if"), you can hire a property manager. I have just one residential and one office property, and combined I spend less than an hour a month on them, mostly record-keeping.

As for stocks, if you pick great mutual funds you can outperform the market over the long term: https://medium.com/financial-strategy/a-simple-investing-method-that-beat-the-s-p-500-for-17-years-and-counting-ed1c99803370. Hardly "gambling"!

As for your preferred methods, they appear to mostly *not* be passive, but rather require effort to create what you want to sell (or earn from), market, and continue creating (especially on Medium) if you want your old articles to continue providing any income.