You can as well build income generating systems, which include; an online store, a digital products or a content channel. It seems these will take your effort up-front, but they can generate income without you needing to be involved every hour of the day.
I'm not so sure about it. For me it sounds like such businesses are too time demanding. You have to be active to send the goods from your online store to the customers and to organize the packages. You need to be an avid reader and researcher to create the content of your online channel. In no way it's passive income. Those sources of income can be powerful side hustles or full time jobs, depending the demand, though.