Residual income means you do something today so that it will continue to pay you for a long time. Residual income does not involve working every day to generate income, residual income means you earn money for a long time from your one-time work.
By posting on Bizdustry, you are earning good money. However, this is not a residual income. You have to post every day, frequently during the day, to earn from the site.
Your gig is hired by a client on Fiverr and you make money by offering your service. This is also not a residual income either.
What exactly is residual income then?
You create a youtube channel, publish good videos. The videos published today will continue to make money for you for 5, 10 years, or even longer. (provided your video is good and you get traffic)
You publish your blog, your blog will continue to make money for you for a long time (provided you are receiving search traffic).
Blogging and vlogging are just a few examples. You can try publishing books on Amazon, you will earn royalty for lifetime. You can also publish articles on the article sites that shares revenue with the publishers, for example, hubpages and medium. You can try crypto investment, etc.
If you want to do online business, consider doing a business that builds you residual income. Some of thee options you can try are, publishing apps on play/app store, building and selling software, etc.