Also, length of relationship is judged on how renewable it is not how long it lasted. You can fire anyone on their first day.
It’s really a question of how open ended the work is not how long someone spends doing it. A restaurant always needs people to cook food and a league always needs a referee as an inherent part of it’s business model. On the other hand a company might only need an architect when designing their new office, aka it’s inherently a finite business need. That architect can largely work at a location and time of their choosing, the referee needs to be where and when the games are taking place. Similarly, an Uber driver needs to be picking someone up at a specific location and specific time going somewhere else or waiting 1 hour doesn’t work.
In general, flexibility in classification of workers almost always plays out poorly for the majority of workers.
Actually you were an employee, just misclassified. If you took them to court you would likely win.
Being able to set your own hours, working part time, working for other employers, quitting at any time - these are all possible in an employee relationship.