Freelancing in Data analytics/data science?

Hi folks, just curious how many here have done part-time freelance work on full-time on Data analytics/data science/ML related areas

Been freelancing for quite a while in data analytics now (4 years, top rated plus on upwork etc) and I'm trying to understand what are the main problems, pain points, issues people face when they tried/tested freelancing apart from traditional jobs in the data world or even in the tech world (web dev, mob dev etc)